Use int rather than java.lang.Integer

Replace Integer wrapper object by int primitive type when an object is
not necessary:
 - The variable must be not null,
 - The result should not make more autoboxing/unboxing than the original
code.

The benefit is:
 - To reduce autoboxing/unboxing to improve the space and time
performance
 - To help the developer to track null pointers in the code

Given:
        Integer assignedInteger = Integer.MIN_VALUE;
        aInteger &= assignedInteger;
        anotherInteger += assignedInteger;
        yetAnotherInteger ^= assignedInteger;

When:
Clean up the code enabling "Use int rather than java.lang.Integer"

Then:
        int assignedInteger = Integer.MIN_VALUE;
        aInteger &= assignedInteger;
        anotherInteger += assignedInteger;
        yetAnotherInteger ^= assignedInteger;

Change-Id: I9361865c2a05d1d9441d0f52ac1018ba59a3fb8f