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  1. Commons BeanUtils
  2. BEANUTILS-268

BeanComparator.compare() doesn't can't handle null values returned by bean properties

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    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Invalid
    • Affects Version/s: 1.7.0
    • Fix Version/s: None
    • Component/s: Bean-Collections
    • Labels:


      I've got a bean that has properties that will, at times, return null values. BeanComparator appears to fail with a NullPointerException. It's difficult to tell exactly where because the exception thrown is a ClassCastException with a message of e.toString(), so all I know is that a NullPointerException happened, not where it happened.

      I suspect that the exception happens inside the compare(Object, Object) method with the call...

      Object value1 = PropertyUtils.getProperty( o1, property );

      Looking into PropertyUtils, and following the path, it seems like the problematic code is in...

      PropertyUtilsBean.getNestedProperty(Object, String)

      That code is rather involved. If I get around to performing a minimal testcase, I'll see if I can narrow down the exception to a particular piece of code. In any case, there's no reason why a bean shouldn't be allowed to return null for a given property.

      My workaround is to add methods for respective properties that are guaranteed to not return null. For instance, if I have a getter called getMyValue(), I create a corresponding method called getMyValueNotNul(). I have to take care with the value it returns, though. The position in a sort for a null value would be different than a literal empty String. So, depending on the Object type, I have to make up values which will either come before all other non-null values or after all other non-null values (I don't recall what the natural order of null values are; whether they come first or last. I know when ordering on a SQLcolumn, null values show up last. Hopefully that behavior is consistent here, but that's beside the point here).

      I hope this can be fixed before 1.8.0 is released!





            • Assignee:
              hoju Jacob Kjome


              • Created:

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