Added comments.

object-pool/src/main/java/com/iluwatar/App.java

@@ -1,5 +1,23 @@
 package com.iluwatar;
 
+/**
+ * 
+ * When it is necessary to work with a large number of objects that are particularly expensive to instantiate 
+ * and each object is only needed for a short period of time, the performance of an entire application may be 
+ * adversely affected. An object pool design pattern may be deemed desirable in cases such as these. 
+ * 
+ * The object pool design pattern creates a set of objects that may be reused. When a new object is needed, it 
+ * is requested from the pool. If a previously prepared object is available it is returned immediately, avoiding 
+ * the instantiation cost. If no objects are present in the pool, a new item is created and returned. When the 
+ * object has been used and is no longer needed, it is returned to the pool, allowing it to be used again in the 
+ * future without repeating the computationally expensive instantiation process. It is important to note that 
+ * once an object has been used and returned, existing references will become invalid.
+ * 
+ * In this example we have created OliphauntPool inheriting from generic ObjectPool. Oliphaunts can be checked
+ * out from the pool and later returned to it. The pool tracks created instances and their status (available,
+ * inUse).
+ *
+ */
 public class App {
 	
     public static void main( String[] args ) {