docs: update .all-contributorsrc [skip ci]

docs: update README.md [skip ci]
2021-01-13 07:39:44 +00:00 · 2021-01-13 07:39:43 +00:00
71 changed files with 1696 additions and 813 deletions
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@ -1368,24 +1368,6 @@
      "contributions": [
        "code"
      ]
-    },
-    {
-      "login": "demirhalil",
-      "name": "Halil Demir",
-      "avatar_url": "https://avatars1.githubusercontent.com/u/22895118?v=4",
-      "profile": "https://github.com/demirhalil",
-      "contributions": [
-        "translation"
-      ]
-    },
-    {
-      "login": "rohit10000",
-      "name": "Rohit Singh",
-      "avatar_url": "https://avatars.githubusercontent.com/u/20845565?v=4",
-      "profile": "https://github.com/rohit10000",
-      "contributions": [
-        "code"
-      ]
    }
  ],
  "contributorsPerLine": 4,
--- a/.gitignore
+++ b/.gitignore
@ -4,8 +4,7 @@ target
 .classpath
 .project
 *.class
-
-### Package Files ###
+# Package Files #
 *.jar
 *.war
 *.ear
@ -14,8 +13,7 @@ target
 *.swp
 datanucleus.log
 /bin/
+/bin/
+/bin/
 *.log
 event-sourcing/Journal.json
-
-### Checkstyle ###
-.checkstyle
--- a/README.md
+++ b/README.md
@ -10,12 +10,12 @@
 [![Coverage](https://sonarcloud.io/api/project_badges/measure?project=iluwatar_java-design-patterns&metric=coverage)](https://sonarcloud.io/dashboard?id=iluwatar_java-design-patterns)
 [![Join the chat at https://gitter.im/iluwatar/java-design-patterns](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/iluwatar/java-design-patterns?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 <!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-152-orange.svg?style=flat-square)](#contributors-)
+[![All Contributors](https://img.shields.io/badge/all_contributors-150-orange.svg?style=flat-square)](#contributors-)
 <!-- ALL-CONTRIBUTORS-BADGE:END -->

 <br/>

-Read in different language : [![CN](/assets/flags/CN.png)**CN**](/zh/README.md),[![KR](/assets/flags/KR.png)**KR**](/ko/README.md),[![FR](/assets/flags/FR.png)**FR**](/fr/README.md),[![TR](/assets/flags/TR.png)**TR**](/tr/README.md),
+Read in different language : [![CN](/assets/flags/CN.png)**CN**](/zh/README.md),[![KR](/assets/flags/KR.png)**KR**](/ko/README.md),[![FR](/assets/flags/FR.png)**FR**](/fr/README.md),

 <br/>

@ -300,8 +300,6 @@ This project is licensed under the terms of the MIT license.
  <tr>
    <td align="center"><a href="http://libkhadir.fr"><img src="https://avatars1.githubusercontent.com/u/45130488?v=4?s=100" width="100px;" alt=""/><br /><sub><b>KHADIR Tayeb</b></sub></a><br /><a href="#translation-tkhadir" title="Translation">🌍</a></td>
    <td align="center"><a href="https://github.com/ignite1771"><img src="https://avatars2.githubusercontent.com/u/59446563?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ignite1771</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ignite1771" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/demirhalil"><img src="https://avatars1.githubusercontent.com/u/22895118?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Halil Demir</b></sub></a><br /><a href="#translation-demirhalil" title="Translation">🌍</a></td>
-    <td align="center"><a href="https://github.com/rohit10000"><img src="https://avatars.githubusercontent.com/u/20845565?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rohit Singh</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=rohit10000" title="Code">💻</a></td>
  </tr>
 </table>

--- a/assets/flags/TR.png
+++ b/assets/flags/TR.png
--- a/data-transfer-object-enum-impl/README.md
+++ b/data-transfer-object-enum-impl/README.md
@ -0,0 +1,54 @@
+---
+layout: pattern
+title: Data Transfer Object
+folder: data-transfer-object
+permalink: /patterns/data-transfer-object/
+categories: Architectural
+tags:
+ - Performance
+---
+
+## Intent
+
+Pass data with multiple attributes in one shot from client to server, to avoid multiple calls to 
+remote server. 
+
+## Explanation
+
+Real world example
+
+> We need to fetch information about customers from remote database. Instead of querying the 
+> attributes one at a time, we use DTOs to transfer all the relevant attributes in a single shot.     
+
+In plain words
+
+> Using DTO relevant information can be fetched with a single backend query. 
+
+Wikipedia says
+
+> In the field of programming a data transfer object (DTO) is an object that carries data between 
+> processes. The motivation for its use is that communication between processes is usually done 
+> resorting to remote interfaces (e.g. web services), where each call is an expensive operation. 
+> Because the majority of the cost of each call is related to the round-trip time between the client 
+> and the server, one way of reducing the number of calls is to use an object (the DTO) that 
+> aggregates the data that would have been transferred by the several calls, but that is served by 
+> one call only.
+
+## Class diagram
+
+![alt text](./etc/dto-enum-uml.png "data-transfer-object")
+
+## Applicability
+
+Use the Data Transfer Object pattern when:
+
+* The client is asking for multiple information. And the information is related.
+* When you want to boost the performance to get resources.
+* You want reduced number of remote calls.
+
+## Credits
+
+* [Design Pattern - Transfer Object Pattern](https://www.tutorialspoint.com/design_pattern/transfer_object_pattern.htm)
+* [Data Transfer Object](https://msdn.microsoft.com/en-us/library/ff649585.aspx)
+* [J2EE Design Patterns](https://www.amazon.com/gp/product/0596004273/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596004273&linkCode=as2&tag=javadesignpat-20&linkId=f27d2644fbe5026ea448791a8ad09c94)
+* [Patterns of Enterprise Application Architecture](https://www.amazon.com/gp/product/0321127420/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0321127420&linkCode=as2&tag=javadesignpat-20&linkId=014237a67c9d46f384b35e10151956bd)
--- a/data-transfer-object-enum-impl/etc/data-transfer-object-enum-impl.urm.puml
+++ b/data-transfer-object-enum-impl/etc/data-transfer-object-enum-impl.urm.puml
@ -0,0 +1,129 @@
+@startuml
+package com.iluwatar.datatransferenum {
+  class App {
+    - LOGGER : Logger {static}
+    + App()
+    + main(args : String[]) {static}
+  }
+  class Product {
+    - cost : Double
+    - id : Long
+    - name : String
+    - price : Double
+    - supplier : String
+    + Product()
+    + getCost() : Double
+    + getId() : Long
+    + getName() : String
+    + getPrice() : Double
+    + getSupplier() : String
+    + setCost(cost : Double) : Product
+    + setId(id : Long) : Product
+    + setName(name : String) : Product
+    + setPrice(price : Double) : Product
+    + setSupplier(supplier : String) : Product
+    + toString() : String
+  }
+  enum ProductDTO {
+    + valueOf(name : String) : ProductDTO {static}
+    + values() : ProductDTO[] {static}
+  }
+  -interface Cost {
+    + getCost() : Double {abstract}
+  }
+  -interface Id {
+    + getId() : Long {abstract}
+  }
+  -interface Name {
+    + getName() : String {abstract}
+  }
+  -interface Price {
+    + getPrice() : Double {abstract}
+  }
+  enum Request {
+    + valueOf(name : String) : Request {static}
+    + values() : Request[] {static}
+  }
+  class Create {
+    - cost : Double
+    - name : String
+    - price : Double
+    - supplier : String
+    + Create()
+    + getCost() : Double
+    + getName() : String
+    + getPrice() : Double
+    + getSupplier() : String
+    + setCost(cost : Double) : Create
+    + setName(name : String) : Create
+    + setPrice(price : Double) : Create
+    + setSupplier(supplier : String) : Create
+  }
+  enum Response {
+    + valueOf(name : String) : Response {static}
+    + values() : Response[] {static}
+  }
+  class Private {
+    - cost : Double
+    - id : Long
+    - name : String
+    - price : Double
+    + Private()
+    + getCost() : Double
+    + getId() : Long
+    + getName() : String
+    + getPrice() : Double
+    + setCost(cost : Double) : Private
+    + setId(id : Long) : Private
+    + setName(name : String) : Private
+    + setPrice(price : Double) : Private
+    + toString() : String
+  }
+  class Public {
+    - id : Long
+    - name : String
+    - price : Double
+    + Public()
+    + getId() : Long
+    + getName() : String
+    + getPrice() : Double
+    + setId(id : Long) : Public
+    + setName(name : String) : Public
+    + setPrice(price : Double) : Public
+    + toString() : String
+  }
+  -interface Supplier {
+    + getSupplier() : String {abstract}
+  }
+  class ProductResource {
+    - products : List<Product>
+    + ProductResource(products : List<Product>)
+    + getAllProductsForAdmin() : List<Private>
+    + getAllProductsForCustomer() : List<Public>
+    + getProducts() : List<Product>
+    + save(createProductDTO : Create)
+  }
+}
+Create ..+ Request
+Request ..+ ProductDTO
+Private ..+ Response
+Supplier ..+ ProductDTO
+Name ..+ ProductDTO
+ProductResource -->  "-products" Product
+Public ..+ Response
+Id ..+ ProductDTO
+Price ..+ ProductDTO
+Response ..+ ProductDTO
+Cost ..+ ProductDTO
+Create ..|> Name 
+Create ..|> Price 
+Create ..|> Cost 
+Create ..|> Supplier 
+Private ..|> Id 
+Private ..|> Name 
+Private ..|> Price 
+Private ..|> Cost 
+Public ..|> Id 
+Public ..|> Name 
+Public ..|> Price 
+@enduml
--- a/data-transfer-object-enum-impl/etc/dto-enum-uml.png
+++ b/data-transfer-object-enum-impl/etc/dto-enum-uml.png
--- a/data-transfer-object-enum-impl/pom.xml
+++ b/data-transfer-object-enum-impl/pom.xml
@ -0,0 +1,61 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    The MIT License
+    Copyright © 2014-2019 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>com.iluwatar</groupId>
+        <artifactId>java-design-patterns</artifactId>
+        <version>1.24.0-SNAPSHOT</version>
+    </parent>
+    <artifactId>data-transfer-object-enum-impl</artifactId>
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <configuration>
+                            <archive>
+                                <manifest>
+                                    <mainClass>com.iluwatar.datatransferenum.App</mainClass>
+                                </manifest>
+                            </archive>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>
--- a/data-transfer-object-enum-impl/src/main/java/com/iluwatar/datatransferenum/App.java
+++ b/data-transfer-object-enum-impl/src/main/java/com/iluwatar/datatransferenum/App.java
@ -0,0 +1,59 @@
+package com.iluwatar.datatransferenum;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * The Data Transfer Object pattern is a design pattern in which an data transfer object is used to
+ * serve related information together to avoid multiple call for each piece of information.
+ *
+ * <p>In this example, ({@link App}) as as product details consumer i.e. client to
+ * request for product details to server.
+ *
+ * <p>productResource ({@link ProductResource}) act as server to serve product information. And
+ * The productDto ({@link ProductDto} is data transfer object to share product information.
+ */
+public class App {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
+
+  /**
+   * Method as act client and request to server for details.
+   *
+   * @param args program argument.
+   */
+  public static void main(String[] args) {
+    Product tv =
+        new Product().setId(1L).setName("TV").setSupplier("Sony").setPrice(1000D).setCost(1090D);
+    Product microwave =
+        new Product().setId(2L).setName("microwave").setSupplier("Delonghi").setPrice(1000D)
+            .setCost(1090D);
+    Product refrigerator =
+        new Product().setId(3L).setName("refrigerator").setSupplier("Botsch").setPrice(1000D)
+            .setCost(1090D);
+    Product airConditioner =
+        new Product().setId(4L).setName("airConditioner").setSupplier("LG").setPrice(1000D)
+            .setCost(1090D);
+    List<Product> products =
+        new ArrayList<>(Arrays.asList(tv, microwave, refrigerator, airConditioner));
+    ProductResource productResource = new ProductResource(products);
+
+    LOGGER.info("####### List of products including sensitive data just for admins: \n {}",
+        Arrays.toString(productResource.getAllProductsForAdmin().toArray()));
+    LOGGER.info("####### List of products for customers: \n {}",
+        Arrays.toString(productResource.getAllProductsForCustomer().toArray()));
+
+    LOGGER.info("####### Going to save Sony PS5 ...");
+    ProductDto.Request.Create createProductRequestDto = new ProductDto.Request.Create()
+        .setName("PS5")
+        .setCost(1000D)
+        .setPrice(1220D)
+        .setSupplier("Sony");
+    productResource.save(createProductRequestDto);
+    LOGGER.info("####### List of products after adding PS5: {}",
+        Arrays.toString(productResource.getProducts().toArray()));
+  }
+}
--- a/data-transfer-object-enum-impl/src/main/java/com/iluwatar/datatransferenum/Product.java
+++ b/data-transfer-object-enum-impl/src/main/java/com/iluwatar/datatransferenum/Product.java
@ -1,27 +1,4 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-package com.iluwatar.datatransfer.product;
+package com.iluwatar.datatransferenum;

 /**
 * {@link Product} is a entity class for product entity. This class act as entity in the demo.
--- a/data-transfer-object-enum-impl/src/main/java/com/iluwatar/datatransferenum/ProductDto.java
+++ b/data-transfer-object-enum-impl/src/main/java/com/iluwatar/datatransferenum/ProductDto.java
@ -1,27 +1,4 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-package com.iluwatar.datatransfer.product;
+package com.iluwatar.datatransferenum;

 /**
 * {@link ProductDto} is a data transfer object POJO.
--- a/data-transfer-object-enum-impl/src/main/java/com/iluwatar/datatransferenum/ProductResource.java
+++ b/data-transfer-object-enum-impl/src/main/java/com/iluwatar/datatransferenum/ProductResource.java
@ -1,27 +1,4 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-package com.iluwatar.datatransfer.product;
+package com.iluwatar.datatransferenum;

 import java.util.List;
 import java.util.stream.Collectors;
--- a/data-transfer-object-enum-impl/src/test/java/com/iluwatar/datatransferenum/AppTest.java
+++ b/data-transfer-object-enum-impl/src/test/java/com/iluwatar/datatransferenum/AppTest.java
@ -0,0 +1,44 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.datatransferenum;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+
+import org.junit.jupiter.api.Test;
+
+class AppTest {
+
+  /**
+   * Issue: Add at least one assertion to this test case.
+   * <p>
+   * Solution: Inserted assertion to check whether the execution of the main method in {@link App#main(String[])}
+   * throws an exception.
+   */
+
+  @Test
+  void shouldExecuteApplicationWithoutException() {
+    assertDoesNotThrow(() -> App.main(new String[] {}));
+  }
+}
--- a/data-transfer-object/src/main/java/com/iluwatar/datatransfer/App.java
+++ b/data-transfer-object/src/main/java/com/iluwatar/datatransfer/App.java
@ -23,13 +23,7 @@

 package com.iluwatar.datatransfer;

-import com.iluwatar.datatransfer.customer.CustomerDto;
-import com.iluwatar.datatransfer.customer.CustomerResource;
-import com.iluwatar.datatransfer.product.Product;
-import com.iluwatar.datatransfer.product.ProductDto;
-import com.iluwatar.datatransfer.product.ProductResource;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.List;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@ -38,17 +32,11 @@ import org.slf4j.LoggerFactory;
 * The Data Transfer Object pattern is a design pattern in which an data transfer object is used to
 * serve related information together to avoid multiple call for each piece of information.
 *
- * <p>In the first example, {@link App} is a customer details consumer i.e. client to
- * request for customer details to server. {@link CustomerResource} act as server to serve customer
- * information. {@link CustomerDto} is data transfer object to share customer information.
- *
- * <p>In the second example, {@link App} is a product details consumer i.e. client to
- * request for product details to server. {@link ProductResource} acts as server to serve
- * product information. {@link ProductDto} is data transfer object to share product information.
- *
- * <p>The pattern implementation is a bit different in each of the examples. The first can be
- * thought as a traditional example and the second is an enum based implementation.
+ * <p>In this example, ({@link App}) as as customer details consumer i.e. client to
+ * request for customer details to server.
 *
+ * <p>CustomerResource ({@link CustomerResource}) act as server to serve customer information. And
+ * The CustomerDto ({@link CustomerDto} is data transfer object to share customer information.
 */
 public class App {

@ -60,8 +48,6 @@ public class App {
   * @param args program argument.
   */
  public static void main(String[] args) {
-
-    // Example 1: Customer DTO
    var customerOne = new CustomerDto("1", "Kelly", "Brown");
    var customerTwo = new CustomerDto("2", "Alfonso", "Bass");
    var customers = new ArrayList<>(List.of(customerOne, customerTwo));
@ -86,53 +72,6 @@ public class App {
    customerResource.save(customerThree);
    allCustomers = customerResource.getAllCustomers();
    printCustomerDetails(allCustomers);
-
-    // Example 2: Product DTO
-    Product tv =
-        new Product().setId(1L).setName("TV").setSupplier("Sony").setPrice(1000D).setCost(1090D);
-    Product microwave =
-        new Product()
-            .setId(2L)
-            .setName("microwave")
-            .setSupplier("Delonghi")
-            .setPrice(1000D)
-            .setCost(1090D);
-    Product refrigerator =
-        new Product()
-            .setId(3L)
-            .setName("refrigerator")
-            .setSupplier("Botsch")
-            .setPrice(1000D)
-            .setCost(1090D);
-    Product airConditioner =
-        new Product()
-            .setId(4L)
-            .setName("airConditioner")
-            .setSupplier("LG")
-            .setPrice(1000D)
-            .setCost(1090D);
-    List<Product> products =
-        new ArrayList<>(Arrays.asList(tv, microwave, refrigerator, airConditioner));
-    ProductResource productResource = new ProductResource(products);
-
-    LOGGER.info(
-        "####### List of products including sensitive data just for admins: \n {}",
-        Arrays.toString(productResource.getAllProductsForAdmin().toArray()));
-    LOGGER.info(
-        "####### List of products for customers: \n {}",
-        Arrays.toString(productResource.getAllProductsForCustomer().toArray()));
-
-    LOGGER.info("####### Going to save Sony PS5 ...");
-    ProductDto.Request.Create createProductRequestDto =
-        new ProductDto.Request.Create()
-            .setName("PS5")
-            .setCost(1000D)
-            .setPrice(1220D)
-            .setSupplier("Sony");
-    productResource.save(createProductRequestDto);
-    LOGGER.info(
-        "####### List of products after adding PS5: {}",
-        Arrays.toString(productResource.getProducts().toArray()));
  }

  private static void printCustomerDetails(List<CustomerDto> allCustomers) {
--- a/data-transfer-object/src/main/java/com/iluwatar/datatransfer/customer/CustomerDto.java
+++ b/data-transfer-object/src/main/java/com/iluwatar/datatransfer/customer/CustomerDto.java
@ -21,7 +21,7 @@
 * THE SOFTWARE.
 */

-package com.iluwatar.datatransfer.customer;
+package com.iluwatar.datatransfer;

 /**
 * {@link CustomerDto} is a data transfer object POJO. Instead of sending individual information to
--- a/data-transfer-object/src/main/java/com/iluwatar/datatransfer/customer/CustomerResource.java
+++ b/data-transfer-object/src/main/java/com/iluwatar/datatransfer/customer/CustomerResource.java
@ -21,7 +21,7 @@
 * THE SOFTWARE.
 */

-package com.iluwatar.datatransfer.customer;
+package com.iluwatar.datatransfer;

 import java.util.List;

--- a/data-transfer-object/src/test/java/com/iluwatar/datatransfer/customer/CustomerResourceTest.java
+++ b/data-transfer-object/src/test/java/com/iluwatar/datatransfer/customer/CustomerResourceTest.java
@ -21,16 +21,13 @@
 * THE SOFTWARE.
 */

-package com.iluwatar.datatransfer.customer;
+package com.iluwatar.datatransfer;

 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;

 import java.util.ArrayList;
 import java.util.List;
-
-import com.iluwatar.datatransfer.customer.CustomerDto;
-import com.iluwatar.datatransfer.customer.CustomerResource;
 import org.junit.jupiter.api.Test;

 /**
--- a/mutex/README.md
+++ b/mutex/README.md
@ -0,0 +1,31 @@
+---
+layout: pattern
+title: Mutex
+folder: mutex
+permalink: /patterns/mutex/
+categories: Concurrency
+tags: 
+ - Decoupling
+---
+
+## Also known as
+
+* Mutual Exclusion Lock
+* Binary Semaphore
+
+## Intent
+Create a lock which only allows a single thread to access a resource at any one instant.
+
+## Class diagram
+![alt text](./etc/mutex.png "Mutex")
+
+## Applicability
+Use a Mutex when
+
+* You need to prevent two threads accessing a critical section at the same time
+* Concurrent access to a resource could lead to a race condition 
+
+## Credits
+
+* [Lock (computer science)](http://en.wikipedia.org/wiki/Lock_(computer_science))
+* [Semaphores](http://tutorials.jenkov.com/java-concurrency/semaphores.html)
--- a/mutex/etc/mutex.png
+++ b/mutex/etc/mutex.png
--- a/mutex/etc/mutex.urm.puml
+++ b/mutex/etc/mutex.urm.puml
@ -0,0 +1,27 @@
+@startuml
+package com.iluwatar.mutex {
+  class App {
+    + App()
+    + main(args : String[]) {static}
+  }
+  class Jar {
+    - beans : int
+    - lock : Lock
+    + Jar(beans : int, lock : Lock)
+    + takeBean() : boolean
+  }
+  interface Lock {
+    + acquire() {abstract}
+    + release() {abstract}
+  }
+  class Mutex {
+    - owner : Object
+    + Mutex()
+    + acquire()
+    + getOwner() : Object
+    + release()
+  }
+}
+Jar -->  "-lock" Lock
+Mutex ..|> Lock 
+@enduml
--- a/mutex/pom.xml
+++ b/mutex/pom.xml
@ -0,0 +1,61 @@
+<?xml version="1.0"?>
+<!--
+
+    The MIT License
+    Copyright © 2014-2019 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.24.0-SNAPSHOT</version>
+  </parent>
+  <artifactId>mutex</artifactId>
+  <dependencies>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-assembly-plugin</artifactId>
+        <executions>
+          <execution>
+            <configuration>
+              <archive>
+                <manifest>
+                  <mainClass>com.iluwatar.mutex.App</mainClass>
+                </manifest>
+              </archive>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>
--- a/mutex/src/main/java/com/iluwatar/mutex/App.java
+++ b/mutex/src/main/java/com/iluwatar/mutex/App.java
@ -0,0 +1,49 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.mutex;
+
+/**
+ * A Mutex prevents multiple threads from accessing a resource simultaneously.
+ *
+ * <p>In this example we have two thieves who are taking beans from a jar. Only one thief can take
+ * a bean at a time. This is ensured by a Mutex lock which must be acquired in order to access the
+ * jar. Each thief attempts to acquire the lock, take a bean and then release the lock. If the lock
+ * has already been acquired, the thief will be prevented from continuing (blocked) until the lock
+ * has been released. The thieves stop taking beans once there are no beans left to take.
+ */
+public class App {
+
+  /**
+   * main method.
+   */
+  public static void main(String[] args) {
+    var mutex = new Mutex();
+    var jar = new Jar(1000, mutex);
+    var peter = new Thief("Peter", jar);
+    var john = new Thief("John", jar);
+    peter.start();
+    john.start();
+  }
+
+}
--- a/mutex/src/main/java/com/iluwatar/mutex/Jar.java
+++ b/mutex/src/main/java/com/iluwatar/mutex/Jar.java
@ -0,0 +1,67 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.mutex;
+
+/**
+ * A Jar has a resource of beans which can only be accessed by a single Thief (thread) at any one
+ * time. A Mutex lock is used to prevent more than one Thief taking a bean simultaneously.
+ */
+public class Jar {
+
+  /**
+   * The lock which must be acquired to access the beans resource.
+   */
+  private final Lock lock;
+
+  /**
+   * The resource within the jar.
+   */
+  private int beans;
+
+  public Jar(int beans, Lock lock) {
+    this.beans = beans;
+    this.lock = lock;
+  }
+
+  /**
+   * Method for a thief to take a bean.
+   */
+  public boolean takeBean() {
+    var success = false;
+    try {
+      lock.acquire();
+      success = beans > 0;
+      if (success) {
+        beans = beans - 1;
+      }
+    } catch (Exception e) {
+      e.printStackTrace();
+    } finally {
+      lock.release();
+    }
+
+    return success;
+  }
+
+}
--- a/mutex/src/main/java/com/iluwatar/mutex/Lock.java
+++ b/mutex/src/main/java/com/iluwatar/mutex/Lock.java
@ -0,0 +1,35 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.mutex;
+
+/**
+ * Lock is an interface for a lock which can be acquired and released.
+ */
+public interface Lock {
+
+  void acquire() throws InterruptedException;
+
+  void release();
+
+}
--- a/mutex/src/main/java/com/iluwatar/mutex/Mutex.java
+++ b/mutex/src/main/java/com/iluwatar/mutex/Mutex.java
@ -0,0 +1,67 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.mutex;
+
+/**
+ * Mutex is an implementation of a mutual exclusion lock.
+ */
+public class Mutex implements Lock {
+
+  /**
+   * The current owner of the lock.
+   */
+  private Object owner;
+
+  /**
+   * Returns the current owner of the Mutex, or null if available.
+   */
+  public Object getOwner() {
+    return owner;
+  }
+
+  /**
+   * Method called by a thread to acquire the lock. If the lock has already been acquired this will
+   * wait until the lock has been released to re-attempt the acquire.
+   */
+  @Override
+  public synchronized void acquire() throws InterruptedException {
+    while (owner != null) {
+      wait();
+    }
+
+    owner = Thread.currentThread();
+  }
+
+  /**
+   * Method called by a thread to release the lock.
+   */
+  @Override
+  public synchronized void release() {
+    if (Thread.currentThread() == owner) {
+      owner = null;
+      notify();
+    }
+  }
+
+}
--- a/strategy/src/main/java/com/iluwatar/strategy/LambdaStrategy.java
+++ b/strategy/src/main/java/com/iluwatar/strategy/LambdaStrategy.java
@ -21,32 +21,47 @@
 * THE SOFTWARE.
 */

-package com.iluwatar.strategy;
+package com.iluwatar.mutex;

 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

-public class LambdaStrategy {
+/**
+ * Thief is a class which continually tries to acquire a jar and take a bean from it. When the jar
+ * is empty the thief stops.
+ */
+public class Thief extends Thread {

-  private static final Logger LOGGER = LoggerFactory.getLogger(LambdaStrategy.class);
+  private static final Logger LOGGER = LoggerFactory.getLogger(Thief.class);

-  public enum Strategy implements DragonSlayingStrategy {
-    MeleeStrategy(() -> LOGGER.info(
-        "With your Excalibur you severe the dragon's head!")),
-    ProjectileStrategy(() -> LOGGER.info(
-        "You shoot the dragon with the magical crossbow and it falls dead on the ground!")),
-    SpellStrategy(() -> LOGGER.info(
-        "You cast the spell of disintegration and the dragon vaporizes in a pile of dust!"));
+  /**
+   * The name of the thief.
+   */
+  private final String name;

-    private final DragonSlayingStrategy dragonSlayingStrategy;
+  /**
+   * The jar.
+   */
+  private final Jar jar;

-    Strategy(DragonSlayingStrategy dragonSlayingStrategy) {
-      this.dragonSlayingStrategy = dragonSlayingStrategy;
-    }
-
-    @Override
-    public void execute() {
-      dragonSlayingStrategy.execute();
-    }
+  public Thief(String name, Jar jar) {
+    this.name = name;
+    this.jar = jar;
  }
+
+  /**
+   * In the run method the thief repeatedly tries to take a bean until none are left.
+   */
+  @Override
+  public void run() {
+    var beans = 0;
+
+    while (jar.takeBean()) {
+      beans = beans + 1;
+      LOGGER.info("{} took a bean.", name);
+    }
+
+    LOGGER.info("{} took {} beans.", name, beans);
+  }
+
 }
--- a/mutex/src/test/java/com/iluwatar/mutex/AppTest.java
+++ b/mutex/src/test/java/com/iluwatar/mutex/AppTest.java
@ -0,0 +1,39 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.mutex;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+/**
+ * Application Test Entrypoint
+ */
+class AppTest {
+
+  @Test
+  void shouldExecuteApplicationWithoutException() {
+    assertDoesNotThrow(() -> App.main(new String[]{}));
+  }
+}
--- a/mutex/src/test/java/com/iluwatar/mutex/JarTest.java
+++ b/mutex/src/test/java/com/iluwatar/mutex/JarTest.java
@ -0,0 +1,45 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.mutex;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+import java.util.stream.IntStream;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test case for taking beans from a Jar
+ */
+public class JarTest {
+
+  @Test
+  public void testTakeBeans() {
+    var mutex = new Mutex();
+    var jar = new Jar(10, mutex);
+    IntStream.range(0, 10).mapToObj(i -> jar.takeBean()).forEach(Assertions::assertTrue);
+    assertFalse(jar.takeBean());
+  }
+
+}
--- a/mutex/src/test/java/com/iluwatar/mutex/MutexTest.java
+++ b/mutex/src/test/java/com/iluwatar/mutex/MutexTest.java
@ -0,0 +1,51 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.mutex;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test case for acquiring and releasing a Mutex
+ */
+public class MutexTest {
+
+  @Test
+  public void acquireReleaseTest() {
+    var mutex = new Mutex();
+    assertNull(mutex.getOwner());
+    try {
+      mutex.acquire();
+      assertEquals(mutex.getOwner(), Thread.currentThread());
+    } catch (InterruptedException e) {
+      fail(e.toString());
+    }
+    mutex.release();
+    assertNull(mutex.getOwner());
+  }
+
+}
--- a/pom.xml
+++ b/pom.xml
@ -141,6 +141,8 @@
        <module>module</module>
        <module>monad</module>
        <module>mute-idiom</module>
+        <module>mutex</module>
+        <module>semaphore</module>
        <module>hexagonal</module>
        <module>abstract-document</module>
        <module>aggregator-microservices</module>
@ -197,6 +199,7 @@
        <module>filterer</module>
        <module>factory</module>
        <module>separated-interface</module>
+        <module>data-transfer-object-enum-impl</module>
        <module>special-case</module>
    </modules>

--- a/registry/pom.xml
+++ b/registry/pom.xml
@ -1,28 +1,4 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<!--
-
-    The MIT License
-    Copyright © 2014-2019 Ilkka Seppälä
-
-    Permission is hereby granted, free of charge, to any person obtaining a copy
-    of this software and associated documentation files (the "Software"), to deal
-    in the Software without restriction, including without limitation the rights
-    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-    copies of the Software, and to permit persons to whom the Software is
-    furnished to do so, subject to the following conditions:
-
-    The above copyright notice and this permission notice shall be included in
-    all copies or substantial portions of the Software.
-
-    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-    THE SOFTWARE.
-
-->
 <project xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
--- a/registry/src/main/java/com/iluwatar/registry/App.java
+++ b/registry/src/main/java/com/iluwatar/registry/App.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.registry;

 import org.slf4j.Logger;
--- a/registry/src/main/java/com/iluwatar/registry/Customer.java
+++ b/registry/src/main/java/com/iluwatar/registry/Customer.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.registry;

 public class Customer {
--- a/registry/src/main/java/com/iluwatar/registry/CustomerRegistry.java
+++ b/registry/src/main/java/com/iluwatar/registry/CustomerRegistry.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.registry;

 import java.util.Map;
--- a/registry/src/test/java/com/iluwatar/registry/CustomerRegistryTest.java
+++ b/registry/src/test/java/com/iluwatar/registry/CustomerRegistryTest.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.registry;

 import org.junit.jupiter.api.BeforeAll;
--- a/semaphore/README.md
+++ b/semaphore/README.md
@ -0,0 +1,33 @@
+---
+layout: pattern
+title: Semaphore
+folder: semaphore
+permalink: /patterns/semaphore/
+categories: Concurrency
+tags: 
+ - Performance
+---
+
+## Also known as
+Counting Semaphore
+
+## Intent
+Create a lock which mediates access to a pool of resources. 
+Only a limited number of threads, specified at the creation 
+of the semaphore, can access the resources at any given time.
+A semaphore which only allows one concurrent access to a resource
+is called a binary semaphore.
+
+## Class diagram
+![alt text](./etc/semaphore.png "Semaphore")
+
+## Applicability
+Use a Semaphore when 
+
+* You have a pool of resources to allocate to different threads
+* Concurrent access to a resource could lead to a race condition 
+
+## Credits
+
+* [Semaphore(programming)] (http://en.wikipedia.org/wiki/Semaphore_(programming))
+* [Semaphores] (http://tutorials.jenkov.com/java-concurrency/semaphores.html)
--- a/semaphore/etc/semaphore.png
+++ b/semaphore/etc/semaphore.png
--- a/semaphore/etc/semaphore.urm.puml
+++ b/semaphore/etc/semaphore.urm.puml
@ -0,0 +1,56 @@
+@startuml
+package com.iluwatar.semaphore {
+  class App {
+    + App()
+    + main(args : String[]) {static}
+  }
+  class Fruit {
+    - type : FruitType
+    + Fruit(type : FruitType)
+    + getType() : FruitType
+    + toString() : String
+  }
+  enum FruitType {
+    + APPLE {static}
+    + LEMON {static}
+    + ORANGE {static}
+    + valueOf(name : String) : FruitType {static}
+    + values() : FruitType[] {static}
+  }
+  class FruitBowl {
+    - fruit : List<Fruit>
+    + FruitBowl()
+    + countFruit() : int
+    + put(f : Fruit)
+    + take() : Fruit
+    + toString() : String
+  }
+  class FruitShop {
+    - available : boolean[]
+    - bowls : FruitBowl[]
+    - semaphore : Semaphore
+    + FruitShop()
+    + countFruit() : int
+    + returnBowl(bowl : FruitBowl)
+    + takeBowl() : FruitBowl
+  }
+  interface Lock {
+    + acquire() {abstract}
+    + release() {abstract}
+  }
+  class Semaphore {
+    - counter : int
+    - licenses : int
+    + Semaphore(licenses : int)
+    + acquire()
+    + getAvailableLicenses() : int
+    + getNumLicenses() : int
+    + release()
+  }
+}
+FruitType ..+ Fruit
+Fruit -->  "-type" FruitType
+FruitShop -->  "-semaphore" Semaphore
+FruitBowl -->  "-fruit" Fruit
+Semaphore ..|> Lock 
+@enduml
--- a/semaphore/pom.xml
+++ b/semaphore/pom.xml
@ -0,0 +1,61 @@
+<?xml version="1.0"?>
+<!--
+
+    The MIT License
+    Copyright © 2014-2019 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.24.0-SNAPSHOT</version>
+  </parent>
+  <artifactId>semaphore</artifactId>
+  <dependencies>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-assembly-plugin</artifactId>
+        <executions>
+          <execution>
+            <configuration>
+              <archive>
+                <manifest>
+                  <mainClass>com.iluwatar.semaphore.App</mainClass>
+                </manifest>
+              </archive>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>
--- a/semaphore/src/main/java/com/iluwatar/semaphore/App.java
+++ b/semaphore/src/main/java/com/iluwatar/semaphore/App.java
@ -0,0 +1,50 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.semaphore;
+
+/**
+ * A Semaphore mediates access by a group of threads to a pool of resources.
+ *
+ * <p>In this example a group of customers are taking fruit from a fruit shop. There is a bowl each
+ * of apples, oranges and lemons. Only one customer can access a bowl simultaneously. A Semaphore is
+ * used to indicate how many resources are currently available and must be acquired in order for a
+ * bowl to be given to a customer. Customers continually try to take fruit until there is no fruit
+ * left in the shop.
+ */
+public class App {
+
+  /**
+   * main method.
+   */
+  public static void main(String[] args) {
+    var shop = new FruitShop();
+    new Customer("Peter", shop).start();
+    new Customer("Paul", shop).start();
+    new Customer("Mary", shop).start();
+    new Customer("John", shop).start();
+    new Customer("Ringo", shop).start();
+    new Customer("George", shop).start();
+  }
+
+}
--- a/semaphore/src/main/java/com/iluwatar/semaphore/Customer.java
+++ b/semaphore/src/main/java/com/iluwatar/semaphore/Customer.java
@ -0,0 +1,82 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.semaphore;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * A Customer attempts to repeatedly take Fruit from the FruitShop by taking Fruit from FruitBowl
+ * instances.
+ */
+public class Customer extends Thread {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(Customer.class);
+
+  /**
+   * Name of the Customer.
+   */
+  private final String name;
+
+  /**
+   * The FruitShop he is using.
+   */
+  private final FruitShop fruitShop;
+
+  /**
+   * Their bowl of Fruit.
+   */
+  private final FruitBowl fruitBowl;
+
+  /**
+   * Customer constructor.
+   */
+  public Customer(String name, FruitShop fruitShop) {
+    this.name = name;
+    this.fruitShop = fruitShop;
+    this.fruitBowl = new FruitBowl();
+  }
+
+  /**
+   * The Customer repeatedly takes Fruit from the FruitShop until no Fruit remains.
+   */
+  public void run() {
+
+    while (fruitShop.countFruit() > 0) {
+      var bowl = fruitShop.takeBowl();
+      if (bowl != null) {
+        var fruit = bowl.take();
+        if (fruit != null) {
+          LOGGER.info("{} took an {}", name, fruit);
+          fruitBowl.put(fruit);
+          fruitShop.returnBowl(bowl);
+        }
+      }
+    }
+
+    LOGGER.info("{} took {}", name, fruitBowl);
+
+  }
+
+}
--- a/semaphore/src/main/java/com/iluwatar/semaphore/Fruit.java
+++ b/semaphore/src/main/java/com/iluwatar/semaphore/Fruit.java
@ -0,0 +1,64 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.semaphore;
+
+/**
+ * Fruit is a resource stored in a FruitBowl.
+ */
+public class Fruit {
+
+  /**
+   * Enumeration of Fruit Types.
+   */
+  public enum FruitType {
+    ORANGE, APPLE, LEMON
+  }
+
+  private final FruitType type;
+
+  public Fruit(FruitType type) {
+    this.type = type;
+  }
+
+  public FruitType getType() {
+    return type;
+  }
+
+  /**
+   * toString method.
+   */
+  public String toString() {
+    switch (type) {
+      case ORANGE:
+        return "Orange";
+      case APPLE:
+        return "Apple";
+      case LEMON:
+        return "Lemon";
+      default:
+        return "";
+    }
+  }
+
+}
--- a/semaphore/src/main/java/com/iluwatar/semaphore/FruitBowl.java
+++ b/semaphore/src/main/java/com/iluwatar/semaphore/FruitBowl.java
@ -0,0 +1,92 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.semaphore;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A FruitBowl contains Fruit.
+ */
+public class FruitBowl {
+
+  private final List<Fruit> fruit = new ArrayList<>();
+
+  /**
+   * Returns the amount of fruits left in bowl.
+   *
+   * @return The amount of Fruit left in the bowl.
+   */
+  public int countFruit() {
+    return fruit.size();
+  }
+
+  /**
+   * Put an item of Fruit into the bowl.
+   *
+   * @param f fruit
+   */
+  public void put(Fruit f) {
+    fruit.add(f);
+  }
+
+  /**
+   * Take an item of Fruit out of the bowl.
+   *
+   * @return The Fruit taken out of the bowl, or null if empty.
+   */
+  public Fruit take() {
+    if (fruit.isEmpty()) {
+      return null;
+    } else {
+      return fruit.remove(0);
+    }
+  }
+
+  /**
+   * toString method.
+   */
+  public String toString() {
+    var apples = 0;
+    var oranges = 0;
+    var lemons = 0;
+
+    for (var f : fruit) {
+      switch (f.getType()) {
+        case APPLE:
+          apples++;
+          break;
+        case ORANGE:
+          oranges++;
+          break;
+        case LEMON:
+          lemons++;
+          break;
+        default:
+      }
+    }
+
+    return apples + " Apples, " + oranges + " Oranges, and " + lemons + " Lemons";
+  }
+}
--- a/semaphore/src/main/java/com/iluwatar/semaphore/FruitShop.java
+++ b/semaphore/src/main/java/com/iluwatar/semaphore/FruitShop.java
@ -0,0 +1,120 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.semaphore;
+
+/**
+ * A FruitShop contains three FruitBowl instances and controls access to them.
+ */
+public class FruitShop {
+
+  /**
+   * The FruitBowl instances stored in the class.
+   */
+  private final FruitBowl[] bowls = {
+      new FruitBowl(),
+      new FruitBowl(),
+      new FruitBowl()
+  };
+
+  /**
+   * Access flags for each of the FruitBowl instances.
+   */
+  private final boolean[] available = {
+      true,
+      true,
+      true
+  };
+
+  /**
+   * The Semaphore that controls access to the class resources.
+   */
+  private final Semaphore semaphore;
+
+  /**
+   * FruitShop constructor.
+   */
+  public FruitShop() {
+    for (var i = 0; i < 100; i++) {
+      bowls[0].put(new Fruit(Fruit.FruitType.APPLE));
+      bowls[1].put(new Fruit(Fruit.FruitType.ORANGE));
+      bowls[2].put(new Fruit(Fruit.FruitType.LEMON));
+    }
+
+    semaphore = new Semaphore(3);
+  }
+
+  /**
+   * Returns the amount of fruits left in shop.
+   *
+   * @return The amount of Fruit left in the shop.
+   */
+  public synchronized int countFruit() {
+    return bowls[0].countFruit() + bowls[1].countFruit() + bowls[2].countFruit();
+  }
+
+  /**
+   * Method called by Customer to get a FruitBowl from the shop. This method will try to acquire the
+   * Semaphore before returning the first available FruitBowl.
+   */
+  public synchronized FruitBowl takeBowl() {
+
+    FruitBowl bowl = null;
+
+    try {
+      semaphore.acquire();
+
+      if (available[0]) {
+        bowl = bowls[0];
+        available[0] = false;
+      } else if (available[1]) {
+        bowl = bowls[1];
+        available[1] = false;
+      } else if (available[2]) {
+        bowl = bowls[2];
+        available[2] = false;
+      }
+
+    } catch (InterruptedException e) {
+      e.printStackTrace();
+    } finally {
+      semaphore.release();
+    }
+    return bowl;
+  }
+
+  /**
+   * Method called by a Customer instance to return a FruitBowl to the shop. This method releases
+   * the Semaphore, making the FruitBowl available to another Customer.
+   */
+  public synchronized void returnBowl(FruitBowl bowl) {
+    if (bowl == bowls[0]) {
+      available[0] = true;
+    } else if (bowl == bowls[1]) {
+      available[1] = true;
+    } else if (bowl == bowls[2]) {
+      available[2] = true;
+    }
+  }
+
+}
--- a/semaphore/src/main/java/com/iluwatar/semaphore/Lock.java
+++ b/semaphore/src/main/java/com/iluwatar/semaphore/Lock.java
@ -0,0 +1,35 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.semaphore;
+
+/**
+ * Lock is an interface for a lock which can be acquired and released.
+ */
+public interface Lock {
+
+  void acquire() throws InterruptedException;
+
+  void release();
+
+}
--- a/semaphore/src/main/java/com/iluwatar/semaphore/Semaphore.java
+++ b/semaphore/src/main/java/com/iluwatar/semaphore/Semaphore.java
@ -0,0 +1,77 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.semaphore;
+
+/**
+ * Semaphore is an implementation of a semaphore lock.
+ */
+public class Semaphore implements Lock {
+
+  private final int licenses;
+  /**
+   * The number of concurrent resource accesses which are allowed.
+   */
+  private int counter;
+
+  public Semaphore(int licenses) {
+    this.licenses = licenses;
+    this.counter = licenses;
+  }
+
+  /**
+   * Returns the number of licenses managed by the Semaphore.
+   */
+  public int getNumLicenses() {
+    return licenses;
+  }
+
+  /**
+   * Returns the number of available licenses.
+   */
+  public int getAvailableLicenses() {
+    return counter;
+  }
+
+  /**
+   * Method called by a thread to acquire the lock. If there are no resources available this will
+   * wait until the lock has been released to re-attempt the acquire.
+   */
+  public synchronized void acquire() throws InterruptedException {
+    while (counter == 0) {
+      wait();
+    }
+    counter = counter - 1;
+  }
+
+  /**
+   * Method called by a thread to release the lock.
+   */
+  public synchronized void release() {
+    if (counter < licenses) {
+      counter = counter + 1;
+      notify();
+    }
+  }
+
+}
--- a/semaphore/src/test/java/com/iluwatar/semaphore/AppTest.java
+++ b/semaphore/src/test/java/com/iluwatar/semaphore/AppTest.java
@ -0,0 +1,39 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.semaphore;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+/**
+ * Application Test Entrypoint
+ */
+class AppTest {
+
+  @Test
+  void shouldExecuteWithoutException() {
+    assertDoesNotThrow(() -> App.main(new String[]{}));
+  }
+}
--- a/semaphore/src/test/java/com/iluwatar/semaphore/FruitBowlTest.java
+++ b/semaphore/src/test/java/com/iluwatar/semaphore/FruitBowlTest.java
@ -0,0 +1,55 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.semaphore;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test taking from and putting Fruit into a FruitBowl
+ */
+public class FruitBowlTest {
+
+  @Test
+  public void fruitBowlTest() {
+    var fbowl = new FruitBowl();
+
+    assertEquals(0, fbowl.countFruit());
+
+    for (var i = 1; i <= 10; i++) {
+      fbowl.put(new Fruit(Fruit.FruitType.LEMON));
+      assertEquals(i, fbowl.countFruit());
+    }
+
+    for (var i = 9; i >= 0; i--) {
+      assertNotNull(fbowl.take());
+      assertEquals(i, fbowl.countFruit());
+    }
+
+    assertNull(fbowl.take());
+  }
+}
--- a/semaphore/src/test/java/com/iluwatar/semaphore/SemaphoreTest.java
+++ b/semaphore/src/test/java/com/iluwatar/semaphore/SemaphoreTest.java
@ -0,0 +1,59 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.semaphore;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test case for acquiring and releasing a Semaphore
+ */
+public class SemaphoreTest {
+
+  @Test
+  public void acquireReleaseTest() {
+    var sphore = new Semaphore(3);
+
+    assertEquals(3, sphore.getAvailableLicenses());
+
+    for (var i = 2; i >= 0; i--) {
+      try {
+        sphore.acquire();
+        assertEquals(i, sphore.getAvailableLicenses());
+      } catch (InterruptedException e) {
+        fail(e.toString());
+      }
+    }
+
+    for (var i = 1; i <= 3; i++) {
+      sphore.release();
+      assertEquals(i, sphore.getAvailableLicenses());
+    }
+
+    sphore.release();
+    assertEquals(3, sphore.getAvailableLicenses());
+  }
+}
--- a/special-case/pom.xml
+++ b/special-case/pom.xml
@ -1,28 +1,4 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<!--
-
-    The MIT License
-    Copyright © 2014-2019 Ilkka Seppälä
-
-    Permission is hereby granted, free of charge, to any person obtaining a copy
-    of this software and associated documentation files (the "Software"), to deal
-    in the Software without restriction, including without limitation the rights
-    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-    copies of the Software, and to permit persons to whom the Software is
-    furnished to do so, subject to the following conditions:
-
-    The above copyright notice and this permission notice shall be included in
-    all copies or substantial portions of the Software.
-
-    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-    THE SOFTWARE.
-
-->
 <project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
--- a/special-case/src/main/java/com/iluwatar/specialcase/App.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/App.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 import org.slf4j.Logger;
--- a/special-case/src/main/java/com/iluwatar/specialcase/ApplicationServices.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/ApplicationServices.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 public interface ApplicationServices {
--- a/special-case/src/main/java/com/iluwatar/specialcase/ApplicationServicesImpl.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/ApplicationServicesImpl.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 public class ApplicationServicesImpl implements ApplicationServices {
--- a/special-case/src/main/java/com/iluwatar/specialcase/Db.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/Db.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 import java.util.HashMap;
--- a/special-case/src/main/java/com/iluwatar/specialcase/DomainServices.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/DomainServices.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 public interface DomainServices {
--- a/special-case/src/main/java/com/iluwatar/specialcase/DomainServicesImpl.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/DomainServicesImpl.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 public class DomainServicesImpl implements DomainServices {
--- a/special-case/src/main/java/com/iluwatar/specialcase/DownForMaintenance.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/DownForMaintenance.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 import org.slf4j.Logger;
--- a/special-case/src/main/java/com/iluwatar/specialcase/InsufficientFunds.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/InsufficientFunds.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 import org.slf4j.Logger;
--- a/special-case/src/main/java/com/iluwatar/specialcase/InvalidUser.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/InvalidUser.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 import org.slf4j.Logger;
--- a/special-case/src/main/java/com/iluwatar/specialcase/MaintenanceLock.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/MaintenanceLock.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 import org.slf4j.Logger;
--- a/special-case/src/main/java/com/iluwatar/specialcase/MoneyTransaction.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/MoneyTransaction.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 public class MoneyTransaction {
--- a/special-case/src/main/java/com/iluwatar/specialcase/OutOfStock.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/OutOfStock.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 import org.slf4j.Logger;
--- a/special-case/src/main/java/com/iluwatar/specialcase/ReceiptDto.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/ReceiptDto.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 import org.slf4j.Logger;
--- a/special-case/src/main/java/com/iluwatar/specialcase/ReceiptViewModel.java
+++ b/special-case/src/main/java/com/iluwatar/specialcase/ReceiptViewModel.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 public interface ReceiptViewModel {
--- a/special-case/src/test/java/com/iluwatar/specialcase/AppTest.java
+++ b/special-case/src/test/java/com/iluwatar/specialcase/AppTest.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
--- a/special-case/src/test/java/com/iluwatar/specialcase/SpecialCasesTest.java
+++ b/special-case/src/test/java/com/iluwatar/specialcase/SpecialCasesTest.java
@ -1,26 +1,3 @@
-/*
- * The MIT License
- * Copyright © 2014-2019 Ilkka Seppälä
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
 package com.iluwatar.specialcase;

 import static org.junit.jupiter.api.Assertions.assertEquals;
--- a/strategy/README.md
+++ b/strategy/README.md
@ -122,51 +122,6 @@ Program output:
    You cast the spell of disintegration and the dragon vaporizes in a pile of dust!    
 ```

-What's more, the new feature Lambda Expressions in Java 8 provides another approach for the implementation:
-
-```java
-public class LambdaStrategy {
-
-  private static final Logger LOGGER = LoggerFactory.getLogger(LambdaStrategy.class);
-
-  public enum Strategy implements DragonSlayingStrategy {
-    MeleeStrategy(() -> LOGGER.info(
-        "With your Excalibur you severe the dragon's head!")),
-    ProjectileStrategy(() -> LOGGER.info(
-        "You shoot the dragon with the magical crossbow and it falls dead on the ground!")),
-    SpellStrategy(() -> LOGGER.info(
-        "You cast the spell of disintegration and the dragon vaporizes in a pile of dust!"));
-
-    private final DragonSlayingStrategy dragonSlayingStrategy;
-
-    Strategy(DragonSlayingStrategy dragonSlayingStrategy) {
-      this.dragonSlayingStrategy = dragonSlayingStrategy;
-    }
-
-    @Override
-    public void execute() {
-      dragonSlayingStrategy.execute();
-    }
-  }
-}
-```
-
-And here's the dragonslayer in action.
-
-```java
-    LOGGER.info("Green dragon spotted ahead!");
-    dragonSlayer.changeStrategy(LambdaStrategy.Strategy.MeleeStrategy);
-    dragonSlayer.goToBattle();
-    LOGGER.info("Red dragon emerges.");
-    dragonSlayer.changeStrategy(LambdaStrategy.Strategy.ProjectileStrategy);
-    dragonSlayer.goToBattle();
-    LOGGER.info("Black dragon lands before you.");
-    dragonSlayer.changeStrategy(LambdaStrategy.Strategy.SpellStrategy);
-    dragonSlayer.goToBattle();
-```
-
-Program output is the same as above one.
-
 ## Class diagram

 ![alt text](./etc/strategy_urm.png "Strategy")
--- a/strategy/etc/strategy.urm.puml
+++ b/strategy/etc/strategy.urm.puml
@ -14,19 +14,6 @@ package com.iluwatar.strategy {
  interface DragonSlayingStrategy {
    + execute() {abstract}
  }
-  class LambdaStrategy {
-    - LOGGER : Logger {static}
-    + LambdaStrategy()
-  }
-  enum Strategy {
-    + MeleeStrategy {static}
-    + ProjectileStrategy {static}
-    + SpellStrategy {static}
-    - dragonSlayingStrategy : DragonSlayingStrategy
-    + execute()
-    + valueOf(name : String) : Strategy {static}
-    + values() : Strategy[] {static}
-  }
  class MeleeStrategy {
    - LOGGER : Logger {static}
    + MeleeStrategy()
@ -43,10 +30,7 @@ package com.iluwatar.strategy {
    + execute()
  }
 }
-Strategy ..+ LambdaStrategy
-Strategy -->  "-dragonSlayingStrategy" DragonSlayingStrategy
 DragonSlayer -->  "-strategy" DragonSlayingStrategy
-Strategy ..|> DragonSlayingStrategy 
 MeleeStrategy ..|> DragonSlayingStrategy 
 ProjectileStrategy ..|> DragonSlayingStrategy 
 SpellStrategy ..|> DragonSlayingStrategy 
--- a/strategy/etc/strategy_urm.png
+++ b/strategy/etc/strategy_urm.png
--- a/strategy/src/main/java/com/iluwatar/strategy/App.java
+++ b/strategy/src/main/java/com/iluwatar/strategy/App.java
@ -45,7 +45,7 @@ public class App {
  
  /**
   * Program entry point.
-   *
+   * 
   * @param args command line args
   */
  public static void main(String[] args) {
@ -60,7 +60,7 @@ public class App {
    dragonSlayer.changeStrategy(new SpellStrategy());
    dragonSlayer.goToBattle();

-    // Java 8 functional implementation Strategy pattern
+    // Java 8 Strategy pattern
    LOGGER.info("Green dragon spotted ahead!");
    dragonSlayer = new DragonSlayer(
        () -> LOGGER.info("With your Excalibur you severe the dragon's head!"));
@ -73,16 +73,5 @@ public class App {
    dragonSlayer.changeStrategy(() -> LOGGER.info(
        "You cast the spell of disintegration and the dragon vaporizes in a pile of dust!"));
    dragonSlayer.goToBattle();
-
-    // Java 8 lambda implementation with enum Strategy pattern
-    LOGGER.info("Green dragon spotted ahead!");
-    dragonSlayer.changeStrategy(LambdaStrategy.Strategy.MeleeStrategy);
-    dragonSlayer.goToBattle();
-    LOGGER.info("Red dragon emerges.");
-    dragonSlayer.changeStrategy(LambdaStrategy.Strategy.ProjectileStrategy);
-    dragonSlayer.goToBattle();
-    LOGGER.info("Black dragon lands before you.");
-    dragonSlayer.changeStrategy(LambdaStrategy.Strategy.SpellStrategy);
-    dragonSlayer.goToBattle();
  }
 }
--- a/tr/README.md
+++ b/tr/README.md
@ -1,42 +0,0 @@
-<!-- Biçimlendirme nedeniyle bu satır boş bırakılmalıdır böylelikle hoş bir görüntüye sahip olabiliriz. örneğin web sitesi -->
-
-![Java CI with Maven](https://github.com/iluwatar/java-design-patterns/workflows/Java%20CI%20with%20Maven/badge.svg)
-[![License MIT](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/iluwatar/java-design-patterns/master/LICENSE.md)
-[![Lines of Code](https://sonarcloud.io/api/project_badges/measure?project=iluwatar_java-design-patterns&metric=ncloc)](https://sonarcloud.io/dashboard?id=iluwatar_java-design-patterns) 
-[![Coverage](https://sonarcloud.io/api/project_badges/measure?project=iluwatar_java-design-patterns&metric=coverage)](https://sonarcloud.io/dashboard?id=iluwatar_java-design-patterns)
-[![Join the chat at https://gitter.im/iluwatar/java-design-patterns](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/iluwatar/java-design-patterns?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
-<!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-148-orange.svg?style=flat-square)](#contributors-)
-<!-- ALL-CONTRIBUTORS-BADGE:END -->
-
-# Giriş
-
-Tasarım desenleri, bir yazılım mühendisi bir uygulamayı veya sistemi tasarlarken yaygın sorunları çözmek için kullanabileceği en iyi çözüm prensipleridir.
-
-Tasarım desenleri, test edilip kanıtlanmış prensipler olduğu için yazılım geliştirme sürecini hızlandırabilir.
-
-Tasarım desenlerini yeniden kullanmak, büyük sorunlara neden olan ince sorunları önlemeye yardımcı olur ve aynı zamanda tasarım desenlerine alışkın olan yazılım mühendisileri ve yazılım mimarları için kod okunabilirliğini artırır.
-
-# Başlangıç
-
-Bu site Java Tasarım Desenlerini sergiliyor. Çözümler, açık kaynak topluluğundan deneyimli yazılım mühendisileri ve yazılım mimarları tarafından geliştirilmiştir. Bu yazılım desenleri, detaylı açıklamalarıyla veya kaynak kodlarına bakılarak göz atılabilir. Kaynak kod örneklerinde iyi derecede açıklayıcı yorum satırlarına sahip olup ve belirli bir tasarım deseninin nasıl uygulanacağına dair programlama dersi olarak düşünülebilir. Savaşta en çok kanıtlanmış açık kaynak Java teknolojilerini kullanıyoruz.
-
-Bu projeye başlamadan önce çeşitli [Yazılım Tasarım İlkelerine](https://java-design-patterns.com/principles/) aşina olmalısınız.
-
-Tüm tasarımlar olabildiğince basit olmalıdır. [KISS](https://en.wikipedia.org/wiki/KISS_principle), [YAGNI](https://en.wikipedia.org/wiki/You_aren%27t_gonna_need_it) ve [Do The Simplest Thing That Could Possibly Work](https://learning.oreilly.com/library/view/extreme-programming-pocket/9781449399849/ch17.html) ilkeleri ile başlamalısınız.
-
-Bu kavramlara aşina olduktan sonra, aşağıdaki yaklaşımlardan herhangi birini kullanarak [mevcut tasarım desenlerini](https://java-design-patterns.com/patterns/) derinlemesine incelemeye başlayabilirsiniz.
-
- İsme göre belirli bir tasarım deseni arayın. Bulamadınız mı? Lütfen yeni bir tasarım deseni için [bizim ile](https://github.com/iluwatar/java-design-patterns/issues) iletişime geçin.
- Performance, Gang of Four ya da Data access gibi etiketleri kullanın.
- Creational(Yaratıcı Tasarım Desenleri), Behavioral(Davranışsal Tasarım Desenleri), ve Structural(Yapısal Tasarım Desenleri) gibi tasarım kategorilerini kullanın.
-
-Umarım bu sitede sunulan nesne yönelimli çözümleri yazılım mimarileriniz için yararlı bulursunuz ve onları geliştirirken bizim kadar eğlenirsiniz.
-
-# Nasıl Katkı Sağlayabilirim
-
-Projeye katkıda bulunmaya istekliysen, ilgili bilgileri [geliştirici wiki'mizde](https://github.com/iluwatar/java-design-patterns/wiki) bulabilirsin. [Gitter](https://gitter.im/iluwatar/java-design-patterns) ile size yardımcı olacağız ve sorularınızı cevaplayacağız.
-
-# Lisans
-
-Bu proje, MIT lisansı koşulları altında lisanslanmıştır.
Author	SHA1	Message	Date
allcontributors[bot]	b4e82ba0c5	docs: update .all-contributorsrc [skip ci]	2021-01-13 07:39:44 +00:00
allcontributors[bot]	d065d759fe	docs: update README.md [skip ci]	2021-01-13 07:39:43 +00:00