why does this return false?

[Ben Harrison]

Integer Ithree = new Integer(2); // 1
Integer Ifour = new Integer(2); // 2
System.out.println( Ithree == Ifour );

wouldn't they unbox and 2 == 2?

[Keith Lynn]

No, because they are both references, == is reference comparison. If one of the operands were a primitive int, the other would be unboxed before the comparison.

[marc weber]

You should also note that with autoboxing, equal values within the range of a byte will box to the same wrapper instance. Specifically, according to JLS - 5.1.7...

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.

For example...

class Equality {
  public static void main(String[] args) {
    Integer i1 = 5;
    Integer i2 = 5;
    Integer i3 = 555;
    Integer i4 = 555;
 
    //same reference here...
    System.out.println("'5' references equal: " + (i1 == i2));
 
    //but (probably) not here...
    System.out.println("'555' references equal: " + (i3 == i4));
  }
}

[Ben Harrison]

So based on:

"No, because they are both references, == is reference comparison. If one of the operands were a primitive int, the other would be unboxed before the comparison."

Wouldn't that mean that since they are both 2 they will point to the same reference variable making the == between them true?

[Keith Lynn]

No, what Marc is talking about is autoboxing.

In your code, you are creating two different objects.

Whenever you use the new operator, a new object is created.

[marc weber]

Yeah, I was kind of moving into another topic. Sorry for the confusion.

[raja kanak]

    
class Equ {
    public static void main(String... args) {
        Integer i1 = new Integer(5);
        Integer i2 = new Integer(5);
        System.out.println(i1==i2);     //false
        Integer i3 = 5;
        Integer i4 = 5;
        System.out.println(i3==i4);     //true
        Integer i5 = new Integer(5);
        Integer i6 = 5;
        System.out.println(i5==i6);     //false
        int i7 = 5;
        Integer i8 = new Integer(5);
        System.out.println(i7==i8);     //true
    }
}

Hope the code above will help.