Explain Testing Objects for Equality in java?

<, >, <= and >= can only be used with numbers and characters. They cannot be used with Strings, booleans, arrays or other compound types since there's no well-defined notion of order for these objects. Is true greater than false? Is "My only regret is that I have but one life to give for my country" greater than "I have a dream"?

Equality is a little easier to test however. true is equal to true and true is not equal to false. Similarly "My only regret is that I have but one life to give for my country" is not equal to "I have a dream." However you might be surprised if you ran this program:
class JackAndJill {

public static void main(String args[]) {

String s1 = new String("Jack went up the hill.");
String s2 = new String("Jack went up the hill.");

if ( s1 == s2 ) {
System.out.println("The strings are the same.");
}

else if ( s1 != s2 ) {
System.out.println("The strings are not the same.");
}
}
}
The result is
The strings are not the same.