Improve Strategy Javadoc

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

@@ -2,7 +2,10 @@ package com.iluwatar.strategy;
 
 /**
  * 
- * Strategy ({@link DragonSlayingStrategy}) encapsulates an algorithm. The containing
+ * The Strategy pattern (also known as the policy pattern) is a software design pattern that 
+ * enables an algorithm's behavior to be selected at runtime.
+ * <p>
+ * In this example ({@link DragonSlayingStrategy}) encapsulates an algorithm. The containing
  * object ({@link DragonSlayer}) can alter its behavior by changing its strategy.
  * 
  */