Update Release Notes

Changes in 1.6.0_21 (6u21)

The full internal version number for this update release is 1.6.0_21-b07 (where "b" means "build"). The external version number is 6u21.

OlsonData 2010i

Java SE 6u21 contains Olson time zone data version 2010i. For more information, refer to Timezone Data Versions in the JRE Software .

Security Baseline

Java SE 6u21 specifies the following security baselines for use with Java Plug-in technology:

JRE Family Version Java SE Security Baseline Java for Business Security Baseline
6 1.6.0_20 1.6.0_20
5.0 1.5.0_22 1.5.0_24
1.4.2 1.4.2_19 1.4.2_26

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

Additional Supported System Configurations

For Java SE 6u21, support has been added for the following system configurations:

  • Oracle Enterprise Linux 5.5
  • Oracle Enterprise Linux 5.4
  • Oracle Enterprise Linux 4.8
  • Red Hat Enterprise Linux 5.5
  • Red Hat Enterprise Linux 5.4
  • Oracle VM
  • Google Chrome 4.0

Refer to the Supported System Configurations page.

Support for Customized Loading Progress Indicators

With Java SE 6u21, you can now enhance the loading experience of an application by providing a customized loading progress indicator (sometimes referred to as a progress bar) to better inform the end user of how much of the application has been downloaded during startup.

Java Hotspot VM 17.0

Java SE 6u21 includes version 17.0 of the Java HotSpot Virtual Machine with improvements to overall quality and features such as compressed object pointers, escape analysis-based optimization, code cache management, the Concurrent Mark-Sweep garbage collector and its successor, the Garbage First (G1) garbage collector. (G1 continues to be available in Early Access via the -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC flag.)

Java VisualVM

Java VisualVM based on VisualVM 1.2.2 is included in Java SE 6u21. This release introduces the following features and enhancements:

  • HeapWalker performance improvements
  • VisualVM-Sampler performance improvements
  • BTrace4VisualVM plugin introduces BTrace 1.1
  • Profiling engine bugfixes
  • Built on NetBeans Platform 6.8

Ensuring Application and Applet Security when Mixing Signed and Unsigned Code

As of the Java SE 6 Update 19 release, when both signed and unsigned code are detected in a Java Web Start application or applet, a warning dialog is raised. As of this release, an enhancement is added allowing some sandboxed jar files to be signed without having to change the JNLP file to request the all-permissions security model. See Mixing Signed and Unsigned Code for more information.

Security Exception Upon Drag-and-Drop

Drag-and-drop would, under certain circumstances, result in a null value being passed instead of the expected data.

Java SE 6u21 provides a fix that lets drag-and-drop operations succeed for signed applications or applications with the accessClipboard permission granted.

Restoration of the Company Name Property Affecting Eclipse Users

As part of Oracle's rebranding of Sun's products, the Company Name property of the java.exe file, the executable file containing Oracle's JRE for Windows, was updated from "Sun Microsystems" to "Oracle" in Java SE 6u21.

After the updated JRE was posted, it was reported that the change affected Eclipse users by causing it to hang when starting Eclipse after updating to the rebranded JRE. A workaround was quickly identified and posted on Eclipse's website, but a wide distribution of the rebranded JRE executable could negatively impact many Eclipse users.

In consideration to Eclipse and other potentially affected users, Oracle has restored the Windows Company Name property value to "Sun Microsystems". This value will be changed to "Oracle" in JDK 7.

The change affected only the Windows version of the JRE, not the versions for Solaris and Linux. To accommodate this update, the Windows build version will increase from Java SE 6u21-b06 to Java SE 6u21-b07.

Update for JDK Installation Failure for Brazillian Portuguese

The JDK installation failure for Brazillian Portuguese issue has been fixed in this release.

The installation of the Java SE 6u21 JDK package resulted in a failure for Brazillian Portuguese locale with the generation of "Error applying transforms. Verify that the specified transform paths are valid" error message. However, this was not an issue for installing the JRE, since the JRE was localized for Brazillian Portuguese.

Bug Fixes

Java SE 6 Update 21 does not contain any additional fixes for security vulnerabilities to its previous release, Java SE 6 Update 20. Users who have Java SE 6 Update 20 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 6u21 Bug Fixes page.