Update Release Notes

Java™ SE 6 Update 25

The full internal version number for this update release is 1.6.0_25-b06 (where "b" means "build"). The external version number is 6u25.


This update release contains important enhancements for Java applications:

  • Improved performance and stability
  • Java HotSpot™ VM 20
  • Support for Internet Explorer 9, Firefox 4 and Chrome 10
  • Improved BigDecimal

Olson Data 2011b

Java SE 6u25 contains Olson time zone data version 2011b. For more information, refer to Timezone Data Versions in the JRE Software .

Security Baselines

The security baselines for the Java SE platform at the time of the release of Java SE 6u25 are specified in the following table:

JRE Family Version Java SE Security Baseline Java for Business Security Baseline
6 1.6.0_24 1.6.0_24
5.0 1.5.0_22 1.5.0_28
1.4.2 1.4.2_19 1.4.2_30

For more information about security baselines, see Deploying Java Applets With Family JRE Versions in Java Plug-in for Internet Explorer .

Additional Supported System Configurations

For Java SE 6u25, support has been added for the following system configurations:

  • Oracle Linux 6
  • Oracle Solaris 11 Express 2010.11
  • Red Hat Enterprise Linux 5.6
  • Windows 7 with SP1
  • Windows 2008 R2 with SP1
  • Internet Explorer 9
  • Firefox 4
  • Chrome 10
  • VirtualBox 4

Refer to the Supported System Configurations page for more information.

Java Hotspot VM 20

Java SE 6u25 includes version 20 of the Java HotSpot Virtual Machine which contains improvements to performance, reliability and diagnostic information.

A new feature in this version of HotSpot is "tiered" compilation in the Server VM that enables it to start quickly as does the Client VM, while achieving superior peak performance. This feature is enabled by specifying -server and -XX:+TieredCompilation command options.

The Garbage First (G1) garbage collector continues to advance with Java SE 6u25, although it remains an experimental option.

HotSpot diagnostic information has been expanded in several ways:

  • Tracking of cumulative Java heap bytes allocated on a per-thread basis
  • On OutOfMemoryError, indication of the faulting thread in the heap dump
  • Improved handling of unexpected exceptions in application native code
  • Better indication of native heap exhaustion
  • More details in hs_err files

Performance Improvement to BigDecimal

Improvements have been made to class BigDecimal enhancing its performance by thirty percent. BigDecimal is enabled by specifying -XX:+AggressiveOpts command option.

Performance Improvement to java.util.logging.LogRecord

The performance of the class java.util.logging.LogRecord has been enhanced. This enhancement improves the efficiency of including source class and method names in java.util.logging log records.

Bug Fixes

Java SE 6u25 does not add any fixes for security vulnerabilities beyond those in Java SE 6u24. Users who have Java SE 6u24 have the latest security fixes and do not need to upgrade to this release to be current on security fixes.

For other bug fixes, see the Java SE 6u25 Bug Fixes page.

Known issue

If you use the setInstallerType("kernel") API from the Java Deployment Toolkit Script to request a Java SE 6u25 Java Kernel installation, currently it will return the Java SE 6u24 Java Kernel installer.