Commented singleton example.

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

@@ -1,5 +1,11 @@
 package com.iluwatar;
 
+/**
+ * 
+ * Singleton pattern ensures that the class (IvoryTower) can have only
+ * one existing instance and provides global access to that instance.
+ *
+ */
 public class App 
 {
     public static void main( String[] args )

singleton/src/main/java/com/iluwatar/IvoryTower.java

@@ -1,5 +1,10 @@
 package com.iluwatar;
 
+/**
+ * 
+ * Singleton class.
+ *
+ */
 public class IvoryTower {
 
 	private static IvoryTower instance = new IvoryTower();