what is the output of the following code? public class test { public static void main(string[] args) { string s1 = new string("welcome to java!"); string s2 = s1.touppercase(); if (s1 == s2) system.out.println("s1 and s2 reference to the same string object"); else if (s1.equals(s2)) system.out.println("s1 and s2 have the same contents"); else system.out.println("s1 and s2 are of different objects"); } }