Exploring Integer - the wrapper class for primitive int

Try `==` and `equals()` for Integer

1. 
   
2. public class IntegerClass {
3. 
   
4. public static void main(String[] args) {
5. 
   
6. Integer i1 = 11;
7. Integer i2 = 11;
8. if(i1 == i2){
9. System.out.println("i1 == i2");
10. }
11. if(i1.equals(i2)){
12. System.out.println("i1.equals(i2)");
13. }
14. /* * * * * * * * * * * * * * * * * * * * * */
16. Integer i3 = 128;
17. Integer i4 = 128;
18. if(i3 == i4){
19. System.out.println("i3 == i4");
20. }else{
21. System.out.println("i3 != i4");
22. }
23. /* * * * * * * * * * * * * * * * * * * * * */
25. if(i3.equals(i4)){
26. System.out.println("i3.equals(i4)");
27. }else{
28. System.out.println("!(i3.equals(i4))");
29. }
30. }
31. }

Line 5 will be actually compiled as Iinteger.valueOf(11)

Thanks to compiler which actually autoboxes primitive values to corresponding wrapper classes.