Why can't the compiler/JVM just make autoboxing “just work”?

Question

Autoboxing is rather scary. While I fully understand the difference between == and .equals I can\'t but help have the follow bug the hell out of m

Answer 1

If you skip autoboxing completely, you still get this behaviour.

final List foo =
  Arrays.asList(Integer.valueOf( 1 ), Integer.valueOf( 1000 ));
final List bar =
  Arrays.asList(Integer.valueOf( 1 ), Integer.valueOf( 1000 ));

System.out.println(foo.get(0) == bar.get(0)); // true
System.out.println(foo.get(1) == bar.get(1)); // false

Be more explicit if you want a specific behavior:

final List foo =
  Arrays.asList( new Integer( 1 ), new Integer( 1000 ));
final List bar =
  Arrays.asList( new Integer( 1 ), new Integer( 1000 ));

System.out.println(foo.get(0) == bar.get(0)); // false
System.out.println(foo.get(1) == bar.get(1)); // false

This is a reason, why Eclipse has autoboxing as a warning by default.