Improve Adapter Javadoc

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

@@ -2,6 +2,12 @@ package com.iluwatar.adapter;
 
 /**
  *
+ * An adapter helps two incompatible interfaces to work together. This is the real 
+ * world definition for an adapter. Interfaces may be incompatible but the inner 
+ * functionality should suit the need. The Adapter design pattern allows otherwise 
+ * incompatible classes to work together by converting the interface of one class 
+ * into an interface expected by the clients.
+ * <p>
  * There are two variations of the Adapter pattern: The class adapter implements
  * the adaptee's interface whereas the object adapter uses composition to
  * contain the adaptee in the adapter object. This example uses the object