diff --git a/dao/src/main/java/com/iluwatar/dao/App.java b/dao/src/main/java/com/iluwatar/dao/App.java
index dd96cf807..ac6794973 100644
--- a/dao/src/main/java/com/iluwatar/dao/App.java
+++ b/dao/src/main/java/com/iluwatar/dao/App.java
@@ -1,47 +1,56 @@
-package com.iluwatar.dao;
-
-import java.util.ArrayList;
-import java.util.List;
-
-/**
- * 
- * With the DAO pattern, we can use various method calls to retrieve/add/delete/update data without directly
- * interacting with the data. The below example demonstrates basic operations(CRUD): select, add, update, and delete.
- */
-public class App {
-
-	public static void main(String[] args) {
-
-		CustomerDaoImpl customerDao = new CustomerDaoImpl(generateSampleCustomers());
-
-		System.out.println("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
-		System.out.println("customerDao.getCusterById(2): " + customerDao.getCusterById(2));
-
-		Customer customer = new Customer(4, "Dan", "Danson");
-		customerDao.addCustomer(customer);
-
-		System.out.println("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
-
-		customer.setFirstName("Daniel");
-		customer.setLastName("Danielson");
-		customerDao.updateCustomer(customer);
-
-		System.out.println("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
-
-		customerDao.deleteCustomer(customer);
-
-		System.out.println("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
-	}
-
-	public static List<Customer> generateSampleCustomers() {
-		Customer customer1 = new Customer(1, "Adam", "Adamson");
-		Customer customer2 = new Customer(2, "Bob", "Bobson");
-		Customer customer3 = new Customer(3, "Carl", "Carlson");
-
-		List<Customer> customers = new ArrayList<Customer>();
-		customers.add(customer1);
-		customers.add(customer2);
-		customers.add(customer3);
-		return customers;
-	}
-}
+package com.iluwatar.dao;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 
+ * With the DAO pattern, we can use various method calls to retrieve/add/delete/update data without directly
+ * interacting with the data. The below example demonstrates basic operations(CRUD): select, add, update, and delete.
+ * 
+ */
+public class App {
+
+	/**
+	 * Program entry point
+	 * @param args command line args
+	 */
+	public static void main(String[] args) {
+
+		CustomerDaoImpl customerDao = new CustomerDaoImpl(generateSampleCustomers());
+
+		System.out.println("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
+		System.out.println("customerDao.getCusterById(2): " + customerDao.getCusterById(2));
+
+		Customer customer = new Customer(4, "Dan", "Danson");
+		customerDao.addCustomer(customer);
+
+		System.out.println("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
+
+		customer.setFirstName("Daniel");
+		customer.setLastName("Danielson");
+		customerDao.updateCustomer(customer);
+
+		System.out.println("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
+
+		customerDao.deleteCustomer(customer);
+
+		System.out.println("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
+	}
+
+	/**
+	 * Generate customers
+	 * @return list of customers
+	 */
+	public static List<Customer> generateSampleCustomers() {
+		Customer customer1 = new Customer(1, "Adam", "Adamson");
+		Customer customer2 = new Customer(2, "Bob", "Bobson");
+		Customer customer3 = new Customer(3, "Carl", "Carlson");
+
+		List<Customer> customers = new ArrayList<Customer>();
+		customers.add(customer1);
+		customers.add(customer2);
+		customers.add(customer3);
+		return customers;
+	}
+}
diff --git a/dao/src/main/java/com/iluwatar/dao/Customer.java b/dao/src/main/java/com/iluwatar/dao/Customer.java
index 7900fee67..8cfdd8034 100644
--- a/dao/src/main/java/com/iluwatar/dao/Customer.java
+++ b/dao/src/main/java/com/iluwatar/dao/Customer.java
@@ -1,6 +1,12 @@
 package com.iluwatar.dao;
 
+/**
+ * 
+ * Customer
+ *
+ */
 public class Customer {
+	
     private int id;
     private String firstName;
     private String lastName;
diff --git a/dao/src/main/java/com/iluwatar/dao/CustomerDao.java b/dao/src/main/java/com/iluwatar/dao/CustomerDao.java
index f201d945d..2a50d2bfb 100644
--- a/dao/src/main/java/com/iluwatar/dao/CustomerDao.java
+++ b/dao/src/main/java/com/iluwatar/dao/CustomerDao.java
@@ -2,7 +2,13 @@ package com.iluwatar.dao;
 
 import java.util.List;
 
+/**
+ * 
+ * CustomerDao
+ *
+ */
 public interface CustomerDao {
+	
     public List<Customer> getAllCustomers();
     public Customer getCusterById(int id);
     public void addCustomer(Customer customer);
diff --git a/dao/src/main/java/com/iluwatar/dao/CustomerDaoImpl.java b/dao/src/main/java/com/iluwatar/dao/CustomerDaoImpl.java
index ff5332798..4403b57ed 100644
--- a/dao/src/main/java/com/iluwatar/dao/CustomerDaoImpl.java
+++ b/dao/src/main/java/com/iluwatar/dao/CustomerDaoImpl.java
@@ -3,11 +3,13 @@ package com.iluwatar.dao;
 import java.util.List;
 
 /**
+ * 
  * The data access object (DAO) is an object that provides an abstract interface to some type of database or other persistence mechanism.
  * By mapping application calls to the persistence layer, DAO provide some specific data operations without exposing details of the database.
  * This isolation supports the Single responsibility principle. It separates what data accesses the application needs, in terms of
  * domain-specific objects and data types (the public interface of the DAO), from how these needs can be satisfied with a specific DBMS,
  * database schema, etc.
+ * 
  */
 public class CustomerDaoImpl implements CustomerDao {
 
diff --git a/dao/src/test/java/com/iluwatar/dao/AppTest.java b/dao/src/test/java/com/iluwatar/dao/AppTest.java
index d45e0ef18..5eb1ebb11 100644
--- a/dao/src/test/java/com/iluwatar/dao/AppTest.java
+++ b/dao/src/test/java/com/iluwatar/dao/AppTest.java
@@ -1,14 +1,19 @@
-package com.iluwatar.dao;
-
-import org.junit.Test;
-
-import com.iluwatar.dao.App;
-
-public class AppTest {
-
-	@Test
-	public void test() {
-		String[] args = {};
-		App.main(args);
-	}
-}
+package com.iluwatar.dao;
+
+import org.junit.Test;
+
+import com.iluwatar.dao.App;
+
+/**
+ * 
+ * Application test
+ *
+ */
+public class AppTest {
+
+	@Test
+	public void test() {
+		String[] args = {};
+		App.main(args);
+	}
+}