Java: Integer equals vs. ==
You can't compare two Integer with a simple == they're objects so most of the time references won't be the same.
There is a trick, with Integer between -128 and 127, references will be the same as autoboxing uses Integer.valueOf() which caches small integers.
If the value p being boxed is true, false, a byte, a char in the range \u0000 to \u007f, or an int or short number between -128 and 127, then let r1 and r2 be the results of any two boxing conversions of p. It is always the case that r1 == r2.
Resources :
- JLS - Boxing
On the same topic :
- autoboxing vs manual boxing java
The JVM is caching Integer values. Hence the comparison with == only works for numbers between -128 and 127.
Refer: #Immutable_Objects_.2F_Wrapper_Class_Caching