String Immutable Nature in Java

String immutable :

String Objects are designed to be immutable object, Since string are created in memory based on their hashcode value it cannot be changed on its same memory location, If you try to change the string value JVM will create a new memory for it and your reference will be pointed to it.

Try this code to verify it.

package com.candidjava;

public class SampleString {

 public static void main(String[] args) {

  // TODO Auto-generated method stub

  String s1 = new String("Candid");

  System.out.println("hashcode of candid: " + s1.hashCode()); // step 1

  s1 = s1.concat("java"); // new object will be created

  System.out.println("hashcode of candidjava: " + s1.hashCode()); // step 2

 }


}