[java] compareTo with primitives -> Integer / int

Is it better to write

int primitive1 = 3, primitive2 = 4;
Integer a = new Integer(primitive1);
Integer b = new Integer(primitive2);
int compare = a.compareTo(b);

or

int primitive1 = 3, primitive2 = 4;
int compare = (primitive1 > primitive2) ? 1 : 0;
if(compare == 0){
    compare = (primitive1 == primitive2) ? 0 : -1;
}

I think the second one is better, should be faster and more memory optimized. But aren't they equal?

If you are using java 8, you can create Comparator by this method:

Comparator.comparingInt(i -> i);

if you would like to compare with reversed order:

Comparator.comparingInt(i -> -i);

May I propose a third

((Integer) a).compareTo(b)  

They're already ints. Why not just use subtraction?

compare = a - b;

Note that Integer.compareTo() doesn't necessarily return only -1, 0 or 1 either.

Wrapping int primitive into Integer object will cost you some memory, but the difference will be only significant in very rare(memory demand) cases (array with 1000+ elements). I will not recommend using new Integer(int a) constructor this way. This will suffice :

Integer a = 3; 

About comparision there is Math.signum(double d).

compare= (int) Math.signum(a-b); 

For pre 1.7 i would say an equivalent to Integer.compare(x, y) is:

Integer.valueOf(x).compareTo(y);

Use Integer.compare(int, int). And don'try to micro-optimize your code unless you can prove that you have a performance issue.

If you need just logical value (as it almost always is), the following one-liner will help you:

boolean ifIntsEqual = !((Math.max(a,b) - Math.min(a, b)) > 0);

And it works even in Java 1.5+, maybe even in 1.1 (i don't have one). Please tell us, if you can test it in 1.5-.

This one will do too:

boolean ifIntsEqual = !((Math.abs(a-b)) > 0);