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  1. JDK
  2. JDK-8198393

Instrumentation.retransformClasses() throws NullPointerException when handling a zero-length array

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      Description

      FULL PRODUCT VERSION :
      openjdk version "9.0.1"
      OpenJDK Runtime Environment (build 9.0.1+11-Ubuntu-1)
      OpenJDK 64-Bit Server VM (build 9.0.1+11-Ubuntu-1, mixed mode)

      ADDITIONAL OS VERSION INFORMATION :
      Linux yushijinhun-laptop 4.15.0-10-generic #11-Ubuntu SMP Tue Feb 13 18:23:35 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

      A DESCRIPTION OF THE PROBLEM :
      In the JavaDoc of Instrumentation.retransformClasses() it says:
      "@param classes array of classes to retransform; a zero-length array is allowed, in this case, this method does nothing"

      However, when I pass a zero-length array into it, I got a NullPointerException and following log:
      *** java.lang.instrument ASSERTION FAILED ***: "numClasses != 0" at JPLISAgent.c line: 1138

      This is where the problem happens: http://hg.openjdk.java.net/jdk7/jdk7/jdk/file/3a4370604bab/src/share/instrument/JPLISAgent.c#l1101

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      Pass a zero-length array into Instrumentation.retransformClasses().

      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      The method does nothing.
      ACTUAL -
      The method throws a NullPointerException.
      And following log is printed:
      *** java.lang.instrument ASSERTION FAILED ***: "numClasses != 0" at JPLISAgent.c line: 1138

      REPRODUCIBILITY :
      This bug can be reproduced always.

      CUSTOMER SUBMITTED WORKAROUND :
      Check the length of the array before passing it into Instrumentation.retransformClasses().

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            • Assignee:
              amenkov Alex Menkov
              Reporter:
              webbuggrp Webbug Group
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              • Created:
                Updated:
                Resolved: