diff --git a/double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/App.java b/double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/App.java
index 10d22a5b2..2a5c65813 100644
--- a/double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/App.java
+++ b/double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/App.java
@@ -5,13 +5,18 @@ import java.util.concurrent.Executors;
 
 /**
  * 
- * In Inventory we store the items with a given size. However, we do not store
+ * In {@link Inventory} we store the items with a given size. However, we do not store
  * more items than the inventory size. To address concurrent access problems we
  * use double checked locking to add item to inventory. In this method, the
  * thread which gets the lock first adds the item.
+ * 
  */
 public class App {
 
+	/**
+	 * Program entry point
+	 * @param args command line args
+	 */
 	public static void main(String[] args) {
 		final Inventory inventory = new Inventory(1000);
 		ExecutorService executorService = Executors.newFixedThreadPool(3);
diff --git a/double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/Inventory.java b/double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/Inventory.java
index e69d30b10..9f663f272 100644
--- a/double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/Inventory.java
+++ b/double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/Inventory.java
@@ -5,6 +5,11 @@ import java.util.List;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 
+/**
+ * 
+ * Inventory
+ *
+ */
 public class Inventory {
 
 	private int inventorySize;
diff --git a/double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/Item.java b/double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/Item.java
index 81db22115..8fc7f3888 100644
--- a/double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/Item.java
+++ b/double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/Item.java
@@ -1,6 +1,12 @@
 package com.iluwatar.doublechecked.locking;
 
+/**
+ * 
+ * Item
+ *
+ */
 public class Item {
-	String name;
-	int level;
+	
+	private String name;
+	private int level;
 }
diff --git a/double-checked-locking/src/test/java/com/iluwatar/doublechecked/locking/AppTest.java b/double-checked-locking/src/test/java/com/iluwatar/doublechecked/locking/AppTest.java
index 51db32c4f..14fd47488 100644
--- a/double-checked-locking/src/test/java/com/iluwatar/doublechecked/locking/AppTest.java
+++ b/double-checked-locking/src/test/java/com/iluwatar/doublechecked/locking/AppTest.java
@@ -4,6 +4,11 @@ import org.junit.Test;
 
 import com.iluwatar.doublechecked.locking.App;
 
+/**
+ * 
+ * Application test
+ *
+ */
 public class AppTest {
 
 	@Test