title: significance of final reference variable
body: <pre><code>String a="A";
  String b="B";
  final String c="C";
  final String d="D";
  
  String e=a+b;
  String f=a+b;
  System.out.println(e==f);//false
  
  String g=c+d;
  String h=c+d;
  System.out.println(g==h);//true
  </code></pre>
  
  <p>Why it is so? String objects are created in a special memory are called string constant pool. But here what is the significance of final variable.</p>