Java Mysteries

What shall be the output of the code?

I found this Question in one of the Java Groups on LinkedIn. Wanted to share with all of you?

public class JavaMysteryCode {       public static void main(String args[]) {             Integer a = 100;             Integer b = 100;             Integer c = 5000;             Integer d = 5000;             if (a == b) {                   System.out.println("a & b Both are Equal");             }             else {                   System.out.println("a & b are Not Equal");             }             if (c == d) {                   System.out.println("c & d Both are Equal");             } else {                   System.out.println("c & d are Not Equal");             }       } }

Out is as Below: a & b Both are Equal c & d are Not Equal // This was not expected right.

At first shot I was also shocked and not able to figure out the Correct output and Why?

Thanks to Gulshan (http://in.linkedin.com/in/gulmathur) for providing the Answer:

JVM has Pool memory for constants from Integer values -128 to 127, so if you create two or more Integer Ref having value from -128 to 127 then they all are pointing to a same memory area. So a and b both having value in range of 1 byte they are referring same memory address while c and d contain value outside this range and memory address for c and d are diff.