Using '==' instead of .equals for Java strings [duplicate]

Answer 1

Can anyone give me an example of the == operator failing?

Example 1:

String s1 = new String("Hello");
String s2 = new String("Hello");
System.out.println(s1 == s2); // false

Example 2:

Integer a=1000,b=1000;
System.out.println(a == b); // false