Question

I was stunned to learn that comparing two Boolean Objects with == can get the wrong answer.

Look at the test code below. Test a and Test c give consistent answers.

Test b fails. It seems that new Boolean(true) can create a separate object with the same value, instead of returning a reference to Boolean.TRUE;

public static void main(String[] args) {
    Boolean a = Boolean.TRUE; 
    Boolean b = new Boolean(true); 
    Boolean c = null; 
    boolean x = true;
    boolean y = false;

    System.out.println("Test a");
    System.out.println(( a == Boolean.TRUE ) ? "TRUE" : "FALSE");
    System.out.println(( Boolean.TRUE.equals(a)) ? "TRUE" : "FALSE");
    System.out.println("Test b");
    System.out.println(( b == Boolean.TRUE ) ? "TRUE" : "FALSE");
    System.out.println(( Boolean.TRUE.equals(b)) ? "TRUE" : "FALSE");
    System.out.println("Test c");
    System.out.println(( c == Boolean.TRUE ) ? "TRUE" : "FALSE");
    System.out.println(( Boolean.TRUE.equals(c)) ? "TRUE" : "FALSE");

    /*  OUTPUT is
    Test a
    TRUE
    TRUE
    Test b
    FALSE
    TRUE
    Test c
    FALSE
    FALSE        
    */
}

Answer 1

Because Boolean is a reference type and == tests if they are the same object in memory then you get false because you allocated b with new.