String s = new String(“xyz”). How many objects has been made after this line of code execute?

Question

The commonly agreed answer to this interview question is that two objects are created by the code. But I don\'t think so; I wrote some code to confirm.

publi         


        

Answer 1

        String s1="Pune";
        String s2="Mumbai";
        String s3="Pune";
        String s4=new String("Mumbai");
        System.out.println("S1 :"+s1.hashCode());  //S1 :2499228
        System.out.println("S2 :"+s2.hashCode());  //S2 :-1979126203
        System.out.println("S3 :"+s3.hashCode());  //S3 :2499228
        System.out.println("S4 :"+s4.hashCode());  //S4 :-1979126203
        System.out.println(s2==s4);     // false

As we can see in the above program we are getting a similar hashcode for s2 and s4 respectively although we are getting false using == operator. == operator is used for reference comparison.

Two objects have been created at "String s4=new String("Mumbai")", one in heap memory and one in stack memory. Therefore s2 compares with s4 which is created in heap memory, not with stack memory.

Answer 2

There is a way to find how many objects are created using the new keyword (String s1=new String("Rajesh")).

public class Rajesh {
    public static void main(String[] args){
        String s1=new String("Rajesh");
        System.out.println(s1+s1.intern());
    }
}

Output:

RajeshRajesh //s1=Rajesh+s2.intern()=Rajesh

Note: As we know the intern method always hit the string constant pool of heap memory.