IV76872: UNEXPECTED NULLPOINTEREXCEPTION WHEN CALLING UNSAFE.COMPAREANDSW AP* WITH A NULL OBJECT ON P AND Z PLATFORMS

APAR status

• Closed as program error.

Error description

• Error Message: NullPointerException in Unsafe.compareAndSwapInt,
  Unsafe.compareAndSwapLong, or Unsafe.compareAndSwapObject when
  the first parameter is NULL. This problem only affects P and Z
  platforms.
  .
  Stack Trace: N/A
  .
  

Local fix

• This problem can be worked around by disabling the JIT compiler
  via the -Xint option. Note that this will have severe
  performance repercussions.
  

Problem summary

• The JIT compiler generates an unnecessary NULL check on the
  first parameter of the compareAndSwap methods in the Unsafe
  class which results in a NullPointerException being thrown if
  the first parameter is NULL. A NULL first parameter is
  acceptable and NullPointerException should not be thrown if one
  is passed.
  

Problem conclusion

• The JIT compiler has been corrected to not generate a NULL check
  in this case.
  .
  This APAR will be fixed in the following Java Releases:
   7 R1 SR3 FP20 (7.1.3.20)
   6 R1 SR8 FP15 (6.1.8.15)
   8 SR2 (8.0.2.0)
   7 SR9 FP20 (7.0.9.20)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the available
  Service Refreshes and Fix Packs can be found at:
   https://www.ibm.com/developerworks/java/jdk/
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

• Fixed component name

  JIT

• Fixed component ID

  620700124

Applicable component levels

• R130 PSY

     UP

• R260 PSY

     UP