FULL PRODUCT VERSION :
java version "1.6.0"
Java(TM) SE Runtime Environment (build 1.6.0-b105)
Java HotSpot(TM) Client VM (build 1.6.0-b105, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP Media Center Edition [Version 5.1.2600] SP2

EXTRA RELEVANT SYSTEM CONFIGURATION :
AOpen MX36LE-UN, Intel Pentium 3 1GHz, SDRAM 1 DIMM 512 PC133

A DESCRIPTION OF THE PROBLEM :
(Un)Boxing does not behave according to JLS 3rd Ed. 5.1.7, 5.1.8:
"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"

boolean TestAutoboxing_Boolean_WRONG() {
      boolean x = true;
      Boolean a = new Boolean(x);
      Boolean b = new Boolean(x);
      return a == b; // Compares by reference
}

boolean TestAutoboxing_Boolean_RIGHT() {
      boolean x = true;
      Boolean a = x;
      Boolean b = x;
      return a == b; // Compares by value
}

Both methods should return "true" proving that:
      a.equals(b) == b.equals(a) == true
but just the second does even when, according to specs, in both cases the assignment to a and b are to be considered "boxings" with the only difference of "whom" is doing the boxing.

The same happens with all 8 types listed in the aformentioned JLS chapter.

Something similar was reported in Bug Id 6212662 but the report was closed stating it wasn't a bug.




STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Just run the example method TestAutoboxing_Boolean_WRONG() and validate the return value.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
When comparing two Boolean types the comparison shoul be always of the same type either by value or by reference but not both.

boolean test1 = TestAutoboxing_Boolean_RIGHT(); //TRUE
boolean test2 = TestAutoboxing_Boolean_WRONG(); //TRUE
boolean result = test1 & test2; //TRUE so is CORRECT
ACTUAL -
boolean test1 = TestAutoboxing_Boolean_RIGHT(); //TRUE
boolean test2 = TestAutoboxing_Boolean_WRONG(); //FALSE
boolean result = test1 & test2; //FALSE so is NOT CORRECT

According to JLS 3rd Ed. 5.1.7, 5.1.8 both methots should return TRUE and the first doesn't.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
boolean TestAutoboxing_Boolean_WRONG() {
      boolean x = true;
      Boolean a = new Boolean(x);
      Boolean b = new Boolean(x);
      return a == b; // Should return TRUE
}

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

CUSTOMER SUBMITTED WORKAROUND :
Avoid using unnecessary boxing. Some IDEs like Idea can actually detect this and suggest alternatives.

Use:
      int x = 9;
      Integer a = x;

Instead of:
      int x = 9;
      Integer a = new Integer(x);

If boxing can't be avoided consider using intemediate variables of native types.