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Double Equals

 
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1: Double a = new Double(Double.NaN);
2: Double b = new Double(Double.NaN);
3:
4: if( Double.NaN == Double.NaN )
5: System.out.println("True");
6: else
7: System.out.println("False");
8:
9: if( a.equals(b) )
10: System.out.println("True");
11: else
12: System.out.println("False");
The answer is
False
True.
I don't understand why the second case is true. It is given that Double.NaN is never equal to Double.NaN.
Can anybody explain why is it so!!!.
Thanx
 
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I think the primitives behave according to IEEE-754 standard, but
the Wrapper has to behave according to the contract of equals method in Object class. This is even clearer in:
Integer iw = new Integer(10);
Float fw = new Float(10.0f);
if (iw.equals(fw))
System.out.println("Equal");
The equals could have returned true. But the contract of equals doesn't allow it. If you check,
if(a.doubleValue() == b.doubleValue())
System.out.println("True doubleValue");
else
System.out.println("False doubleValue");
it returns false.
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