Update App.java

it is important to note that the singleton pattern is inherently unsafe for distributed environments, since the initialization state is not mirrored across different instances of the java vm

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

@@ -3,7 +3,7 @@ package com.iluwatar;
 /**
  *
  * Singleton pattern ensures that the class (IvoryTower) can have only one
- * existing instance and provides global access to that instance.
+ * existing instance per java vm instance and provides global access to that it.
  *
  * http://stackoverflow.com/questions/70689/what-is-an-efficient-way-to-implement-a-singleton-pattern-in-java
  *