On virtual machines and expected behaviour

Ever tried running this on your ENTERPRISE VIRTUAL MACHINE?
Integer a = 1000;
 Integer b = 1000;
 System.out.println("a == b (1000 == 1000): " + (a == b));

 Integer aa = 100;
 Integer bb = 100;
 System.out.println("aa == bb (100 == 100): " + (aa == bb));
Guess what's the output, run it and report back.

>>24
We can either remove the caching or store a table of already seen Integer objects and reference into it. The second options is obviously impractical, while the first can be done easily. The question is, why do we need to make an operation with undefined behavior "consistent" on its results?