Merge branch 'master' of https://github.com/iluwatar/java-design-patterns into refactor-dao

decorator/src/main/java/com/iluwatar/decorator/Troll.java

@@ -29,6 +29,7 @@ package com.iluwatar.decorator;
  */
 public class Troll implements Hostile {
 
+  @Override
   public void attack() {
     System.out.println("The troll swings at you with a club!");
   }
@@ -38,6 +39,7 @@ public class Troll implements Hostile {
     return 10;
   }
 
+  @Override
   public void fleeBattle() {
     System.out.println("The troll shrieks in horror and runs away!");
   }

mute-idiom/README.md

@@ -0,0 +1,28 @@
+---
+layout: pattern
+title: Mute Idiom
+folder: mute-idiom
+permalink: /patterns/mute-idiom/
+categories: Other
+tags: 
+ - Java
+ - Difficulty-Beginner
+ - Idiom
+---
+
+## Intent
+Provide a template to supress any exceptions that either are declared but cannot occur or should only be logged;
+while executing some business logic. The template removes the need to write repeated `try-catch` blocks.
+
+
+![alt text](./etc/mute-idiom.png "Mute Idiom")
+
+## Applicability
+Use this idiom when
+
+* an API declares some exception but can never throw that exception. Eg. ByteArrayOutputStream bulk write method.
+* you need to suppress some exception just by logging it, such as closing a resource.
+
+## Credits
+
+* [JOOQ: Mute Design Pattern](http://blog.jooq.org/2016/02/18/the-mute-design-pattern/)

mute-idiom/etc/mute-idiom.ucls

@@ -0,0 +1,71 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<class-diagram version="1.1.8" icons="true" automaticImage="PNG" always-add-relationships="false" generalizations="true" 
+  realizations="true" associations="true" dependencies="true" nesting-relationships="true">  
+  <class id="1" language="java" name="com.iluwatar.mute.App" project="mute-idiom" 
+    file="/mute-idiom/src/main/java/com/iluwatar/mute/App.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="168" y="234"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="false" static="true"/>      
+      <operations public="true" package="true" protected="true" private="false" static="true"/>    
+    </display>  
+  </class>  
+  <class id="2" language="java" name="com.iluwatar.mute.Mute" project="mute-idiom" 
+    file="/mute-idiom/src/main/java/com/iluwatar/mute/Mute.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="115" width="203" x="70" y="375"/>    
+    <display autosize="false" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="false" static="true"/>    
+    </display>  
+  </class>  
+  <interface id="3" language="java" name="com.iluwatar.mute.CheckedRunnable" project="mute-idiom" 
+    file="/mute-idiom/src/main/java/com/iluwatar/mute/CheckedRunnable.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="407" y="432"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </interface>  
+  <interface id="4" language="java" name="com.iluwatar.mute.Resource" project="mute-idiom" 
+    file="/mute-idiom/src/main/java/com/iluwatar/mute/Resource.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="383" y="235"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </interface>  
+  <interface id="5" language="java" name="java.io.Closeable" project="dao" 
+    file="/opt/Softwares/Eclipses/MARS/eclipse/jre/lib/rt.jar" binary="true" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="384" y="109"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </interface>  
+  <dependency id="6">    
+    <end type="SOURCE" refId="1"/>    
+    <end type="TARGET" refId="4"/>  
+  </dependency>  
+  <dependency id="7">    
+    <end type="SOURCE" refId="1"/>    
+    <end type="TARGET" refId="2"/>  
+  </dependency>  
+  <dependency id="8">    
+    <end type="SOURCE" refId="2"/>    
+    <end type="TARGET" refId="3"/>  
+  </dependency>  
+  <generalization id="9">    
+    <end type="SOURCE" refId="4"/>    
+    <end type="TARGET" refId="5"/>  
+  </generalization>  
+  <classifier-display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+    sort-features="false" accessors="true" visibility="true">    
+    <attributes public="true" package="true" protected="true" private="true" static="true"/>    
+    <operations public="true" package="true" protected="true" private="true" static="true"/>  
+  </classifier-display>  
+  <association-display labels="true" multiplicity="true"/>
+</class-diagram>

mute-idiom/pom.xml

@@ -0,0 +1,34 @@
+<?xml version="1.0"?>
+<!-- The MIT License Copyright (c) 2014 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>1.11.0-SNAPSHOT</version>
+	</parent>
+	<artifactId>mute-idiom</artifactId>
+	<dependencies>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+</project>

mute-idiom/src/main/java/com/iluwatar/mute/App.java

@@ -0,0 +1,103 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 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.mute;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.sql.SQLException;
+
+/**
+ * Mute pattern is utilized when we need to suppress an exception due to an API flaw or in 
+ * situation when all we can do to handle the exception is to log it. 
+ * This pattern should not be used everywhere. It is very important to logically handle the 
+ * exceptions in a system, but some situations like the ones described above require this pattern, 
+ * so that we don't need to repeat 
+ * <pre>
+ * <code>
+ *   try {
+ *     // code that may throwing exception we need to ignore or may never be thrown
+ *   } catch (Exception ex) {
+ *     // ignore by logging or throw error if unexpected exception occurs
+ *   }
+ * </code>
+ * </pre> every time we need to ignore an exception.
+ * 
+ */
+public class App {
+
+  /**
+   * Program entry point.
+   * 
+   * @param args command line args.
+   * @throws Exception if any exception occurs
+   */
+  public static void main(String[] args) throws Exception {
+
+    useOfLoggedMute();
+
+    useOfMute();
+  }
+
+  /*
+   * Typically used when the API declares some exception but cannot do so. Usually a 
+   * signature mistake.In this example out is not supposed to throw exception as it is a
+   * ByteArrayOutputStream. So we utilize mute, which will throw AssertionError if unexpected
+   * exception occurs.
+   */
+  private static void useOfMute() {
+    ByteArrayOutputStream out = new ByteArrayOutputStream();
+    Mute.mute(() -> out.write("Hello".getBytes()));
+  }
+
+  private static void useOfLoggedMute() throws SQLException {
+    Resource resource = null;
+    try {
+      resource = acquireResource();
+      utilizeResource(resource);
+    } finally {
+      closeResource(resource);
+    }
+  }
+
+  /*
+   * All we can do while failed close of a resource is to log it.
+   */
+  private static void closeResource(Resource resource) {
+    Mute.loggedMute(() -> resource.close());
+  }
+
+  private static void utilizeResource(Resource resource) throws SQLException {
+    System.out.println("Utilizing acquired resource: " + resource);
+  }
+
+  private static Resource acquireResource() throws SQLException {
+    return new Resource() {
+      
+      @Override
+      public void close() throws IOException {
+        throw new IOException("Error in closing resource: " + this);
+      }
+    };
+  }
+}

mute-idiom/src/main/java/com/iluwatar/mute/CheckedRunnable.java

@@ -0,0 +1,37 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 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.mute;
+
+/**
+ * A runnable which may throw exception on execution.
+ *
+ */
+@FunctionalInterface
+public interface CheckedRunnable {
+  /**
+   * Same as {@link Runnable#run()} with a possibility of exception in execution.
+   * @throws Exception if any exception occurs.
+   */
+  void run() throws Exception;
+}

mute-idiom/src/main/java/com/iluwatar/mute/Mute.java

@@ -0,0 +1,68 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 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.mute;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+
+/**
+ * A utility class that allows you to utilize mute idiom.
+ */
+public final class Mute {
+  
+  // The constructor is never meant to be called.
+  private Mute() {}
+
+  /**
+   * Executes the <code>runnable</code> and throws the exception occurred within a {@link AssertionError}.
+   * This method should be utilized to mute the operations that are guaranteed not to throw an exception.
+   * For instance {@link ByteArrayOutputStream#write(byte[])} declares in it's signature that it can throw
+   * an {@link IOException}, but in reality it cannot. This is because the bulk write method is not overridden
+   * in {@link ByteArrayOutputStream}.
+   * 
+   * @param runnable a runnable that should never throw an exception on execution.
+   */
+  public static void mute(CheckedRunnable runnable) {
+    try {
+      runnable.run();
+    } catch (Exception e) {
+      throw new AssertionError(e);
+    }
+  }
+
+  /**
+   * Executes the <code>runnable</code> and logs the exception occurred on {@link System#err}.
+   * This method should be utilized to mute the operations about which most you can do is log.
+   * For instance while closing a connection to database, or cleaning up a resource, 
+   * all you can do is log the exception occurred.
+   * 
+   * @param runnable a runnable that may throw an exception on execution.
+   */
+  public static void loggedMute(CheckedRunnable runnable) {
+    try {
+      runnable.run();
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+}

mute-idiom/src/main/java/com/iluwatar/mute/Resource.java

@@ -0,0 +1,35 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 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.mute;
+
+import java.io.Closeable;
+
+/**
+ * Represents any resource that the application might acquire and that must be closed
+ * after it is utilized. Example of such resources can be a database connection, open
+ * files, sockets. 
+ */
+public interface Resource extends Closeable {
+
+}

mute-idiom/src/test/java/com/iluwatar/mute/AppTest.java

@@ -0,0 +1,38 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 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.mute;
+
+import org.junit.Test;
+
+/**
+ * Tests that Mute idiom example runs without errors.
+ *
+ */
+public class AppTest {
+
+  @Test
+  public void test() throws Exception {
+    App.main(null);
+  }
+}

mute-idiom/src/test/java/com/iluwatar/mute/MuteTest.java

@@ -0,0 +1,78 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 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.mute;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.PrintStream;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+public class MuteTest {
+
+  private static final String MESSAGE = "should not occur";
+  
+  @Rule public ExpectedException exception = ExpectedException.none();
+  
+  @Test
+  public void muteShouldRunTheCheckedRunnableAndNotThrowAnyExceptionIfCheckedRunnableDoesNotThrowAnyException() {
+    Mute.mute(() -> methodNotThrowingAnyException());
+  }
+  
+  @Test
+  public void muteShouldRethrowUnexpectedExceptionAsAssertionError() throws Exception {
+    exception.expect(AssertionError.class);
+    exception.expectMessage(MESSAGE);
+    
+    Mute.mute(() -> methodThrowingException());
+  }
+  
+  @Test
+  public void loggedMuteShouldRunTheCheckedRunnableAndNotThrowAnyExceptionIfCheckedRunnableDoesNotThrowAnyException() {
+    Mute.loggedMute(() -> methodNotThrowingAnyException());
+  }
+  
+  @Test
+  public void loggedMuteShouldLogExceptionTraceBeforeSwallowingIt() throws IOException {
+    ByteArrayOutputStream stream = new ByteArrayOutputStream();
+    System.setErr(new PrintStream(stream));
+    
+    Mute.loggedMute(() -> methodThrowingException());
+    
+    assertTrue(new String(stream.toByteArray()).contains(MESSAGE));
+  }
+  
+  
+  private void methodNotThrowingAnyException() {
+    System.out.println("Executed successfully");
+  }
+  
+  private void methodThrowingException() throws Exception {
+    throw new Exception(MESSAGE);
+  }
+}

pom.xml

@@ -124,6 +124,7 @@
 		<module>feature-toggle</module>
 		<module>value-object</module>
 		<module>monad</module>
+		<module>mute-idiom</module>
 	</modules>
 
 	<dependencyManagement>

repository/src/main/java/com/iluwatar/repository/App.java

@@ -100,6 +100,8 @@ public class App {
       System.out.println(person);
     }
 
+    repository.deleteAll();
+    
     context.close();
 
   }

repository/src/main/resources/applicationContext.xml

@@ -54,7 +54,8 @@
     <property name="jpaProperties">
       <map>
         <entry key="hibernate.dialect" value="org.hibernate.dialect.H2Dialect" />
-        <entry key="hibernate.hbm2ddl.auto" value="create-drop" />
+        <entry key="hibernate.hbm2ddl.auto" value="create" />
+        <entry key="hibernate.show_sql" value="false" />
       </map>
     </property>
   </bean>

strategy/src/main/java/com/iluwatar/strategy/MeleeStrategy.java

@@ -31,6 +31,6 @@ public class MeleeStrategy implements DragonSlayingStrategy {
 
   @Override
   public void execute() {
-    System.out.println("With your Excalibur you severe the dragon's head!");
+    System.out.println("With your Excalibur you sever the dragon's head!");
   }
 }

strategy/src/test/java/com/iluwatar/strategy/DragonSlayingStrategyTest.java

@@ -52,7 +52,7 @@ public class DragonSlayingStrategyTest {
     return Arrays.asList(
         new Object[]{
             new MeleeStrategy(),
-            "With your Excalibur you severe the dragon's head!"
+            "With your Excalibur you sever the dragon's head!"
         },
         new Object[]{
             new ProjectileStrategy(),