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Editorial Team
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Asked: 2026-05-26T00:58:52+00:00

I’m trying to do a code review for our project using FindBugs. we have

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I’m trying to do a code review for our project using FindBugs.

we have a method to generate unique id (randomly) :

 public static String generateUUID(int base){

    return String.valueOf(getCurrentTimeInNanos((long)base))  + 

                     String.valueOf(Math.abs(random.nextInt()));
 }

and findBugs indicates RV_ABSOLUTE_VALUE_OF_RANDOM_INT warning (RV: Bad attempt to compute absolute value of signed 32-bit random integer ) , i guess the problem is in String.valueOf(Math.abs(random.nextInt()).

Does anyone have an explanation for why is this and how to fix it ?

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1 Answer

  1. Editorial Team

    Maybe it is because Math.abs can actually return negative results for integer inputs:

    assertTrue( Math.abs(Integer.MIN_VALUE) < 0 );

    It only does this for MIN_VALUE, though, because -MIN_VALUE cannot be represented. Kind of an overflow problem.

    As for how to fix it:

    • don’t make your own UUID. Use java.util.UUID.

    • cast the random number to long before calling Math.abs

    • use random.nextInt(Integer.MAX_VALUE) to get a number from 0 to MAX_VALUE – 1

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