Added code comments.

resource-acquisition-is-initialization/src/main/java/com/iluwatar/App.java

@@ -1,5 +1,29 @@
 package com.iluwatar;
 
+/**
+ * 
+ * Resource Acquisition Is Initialization pattern was developed
+ * for exception safe resource management by C++ creator Bjarne
+ * Stroustrup.
+ * 
+ * In RAII resource is tied to object lifetime: resource allocation
+ * is done during object creation while resource deallocation is
+ * done during object destruction.
+ * 
+ * In Java RAII is achieved with try-with-resources statement and
+ * interfaces Closeable and AutoCloseable. The try-with-resources 
+ * statement ensures that each resource is closed at the end of the 
+ * statement. Any object that implements java.lang.AutoCloseable, which 
+ * includes all objects which implement java.io.Closeable, can be used 
+ * as a resource.
+ *
+ * In this example, SlidingDoor implements AutoCloseable and 
+ * TreasureChest implements Closeable. Running the example, we can
+ * observe that both resources are automatically closed.
+ * 
+ * http://docs.oracle.com/javase/7/docs/technotes/guides/language/try-with-resources.html
+ *
+ */
 public class App {
 	
 	public static void main( String[] args ) throws Exception {

resource-acquisition-is-initialization/src/main/java/com/iluwatar/SlidingDoor.java

@@ -1,5 +1,10 @@
 package com.iluwatar;
 
+/**
+ * 
+ * SlidingDoor resource
+ *
+ */
 public class SlidingDoor implements AutoCloseable {
 
 	public SlidingDoor() {

resource-acquisition-is-initialization/src/main/java/com/iluwatar/TreasureChest.java

@@ -3,6 +3,11 @@ package com.iluwatar;
 import java.io.Closeable;
 import java.io.IOException;
 
+/**
+ * 
+ * TreasureChest resource
+ *
+ */
 public class TreasureChest implements Closeable {
 
 	public TreasureChest() {