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  1. JDK
  2. JDK-8040892

Incorrect message in Exception thrown by Collectors.toMap(Function,Function)

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    • Icon: Bug Bug
    • Resolution: Fixed
    • Icon: P4 P4
    • 9
    • 8
    • core-libs

      For this very short test case:

      Stream.of(3, 5).collect(toMap(i -> i % 2, Integer::reverse));

      The following exception is produced:

      Exception in thread "main" java.lang.IllegalStateException: Duplicate key -1073741824
      at java.util.stream.Collectors.lambda$throwingMerger$90(Collectors.java:133)

      Clearly, the value being printed is not the key, but rather one of two values for which there is a key collision.

      The message thrown should either display at least two values for which there is a key collision or ideally the key for which the collision happened.

            plevart Peter Levart
            misterm Michael Santos (Inactive)
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              Created:
              Updated:
              Resolved: