FULL PRODUCT VERSION :
java version "1.5.0_05"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_05-b05)
Java HotSpot(TM) Client VM (build 1.5.0_05-b05, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Linux em-09.fitc.org.ar 2.6.11-6mdk #1 Tue Mar 22 16:04:32 CET 2005 i686 Intel(R) Pentium(R) 4 CPU 2.26GHz unknown GNU/Linux


A DESCRIPTION OF THE PROBLEM :
The specification says that "all methods in this class [java.math.BigInteger] throw NullPointerException when passed a null object reference for any input parameter", but BigInteger.ZERO.multiply(null) returns 0.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
execute the sample program

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
NullPointerException to be throw
ACTUAL -
return BigInteger.ZERO

ERROR MESSAGES/STACK TRACES THAT OCCUR :
... the problem is there is no error message (but there should be)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class ZeroByNull{
    public static void main (String[] args){
        System.out.println(java.math.BigInteger.ZERO.multiply(null));
    }
}
---------- END SOURCE ----------