IJ07886: JAVA JIT: INCORRECT CALCULATIONS WHEN USING NUMBERFORMAT.FORMAT() AND BIGDECIMAL.{FLOAT/DOUBLE}VALUE()

APAR status

• Closed as program error.

Error description

• Error Message: The results of a the following code is incorrect:
  DecimalFormat.format( BigDecimal.doubleValue() / myDouble )
  .
  Stack Trace: N/A
  .
  

Local fix

• The problem can be avoided by using the following Java command
  line option:
  -Xjit:disableDecimalFormatPeephole
  This is unlikely to have a noticeable impact on performance, but
  in might be noticeable in extreme cases.
  

Problem summary

• When optimizing NumberFormat.format(BigDecimal.doubleValue())
  cases the JIT could incorrectly detected some sequences allowing
  for the JIT to incorrectly replace code sequences where the
  BigDecimal.doubleValue() result is modified before being passed
  as a parameter to NumberFormat.format().
  

Problem conclusion

• The JIT was modified so that it will only optimize cases where
  the BigDecimal.doubleValue() is passed directly to
  NumberFormat.format().
  .
  This APAR will be fixed in the following Java Releases:
   8 SR5 FP21 (8.0.5.21)
   7 R1 SR4 FP35 (7.1.4.35)
  Except with z/OS where this APAR is fixed in:
   8 SR5 FP22 (8.0.5.22)
  .
  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

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