Q1: What will be the output of the program?

public class StringRef 
{
    public static void main(String [] args) 
    {
        String s1 = 'abc';
        String s2 = 'def';
        String s3 = s2;   /* Line 7 */
        s2 = 'ghi';
        System.out.println(s1 + s2 + s3);
    }
}

ANS:A - abcdefghi

After line 7 executes, both s2 and s3 refer to a String object that contains the value 'def'. When line 8 executes, a new String object is created with the value 'ghi', to which s2 refers. The reference variable s3 still refers to the (immutable) String object with the value 'def'.