FULL PRODUCT VERSION :
java version "1.5.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-b64)
Java HotSpot(TM) Client VM (build 1.5.0-b64, mixed mode, sharing)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
Comparing a primitive value to an Object does either boxing or unboxing, depending on the compile time type of the Object argument.

In case boxing is selected, the compiler should report error, since comparing a newly created object with some any other object is always false.

Please refer to the code below.



STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
The code below.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
It should not compile the second and third checks.

ACTUAL -
It compiles, and reports "false".


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------

    public static void main(String[] args) {
        double a = 1.5;
        Double b = 1.5;
        if (a == b)
            System.out.println("TRUE: Did unwap for b, thus, got equal doubles");
        else
            System.out.println("FALSE: Did wrap for a, thus, got different Double objects");

        Number c = b;
        if (a == c)
            System.out.println("TRUE: Did unwap for c, thus, got equal doubles");
        else
            System.out.println("FALSE: Did wrap for a, thus, got different Double objects");

        Object d = b;
        if (a == d)
            System.out.println("TRUE: Did unwap for d, thus, got equal doubles");
        else
            System.out.println("FALSE: Did wrap for a, thus, got different Double objects");

        // TRUE: Did unwap for b, thus, got equal doubles
        // FALSE: Did wrap for a, thus, got different Double objects
        // FALSE: Did wrap for a, thus, got different Double objects
    }


It also lead sometime to strange results as:

 public static void main(String[] args) {
        int a1 = 4;
        Integer b1 = 4;
        Object c1 = b1;
        System.out.println(a1 == c1); // prints TRUE

        int a2 = 400;
        Integer b2 = 400;
        Object c2 = b2;
        System.out.println(a2 == c2); // prints FALSE
    }


---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Be careful...
###@###.### 2004-12-27 06:38:52 GMT