Java™ SE Embedded 7u21 Release Notes

Java™ SE Embedded 7 Update 21 Runtime Environment

This document summarizes the functionality and known issues of Java SE Embedded 7 Update 21 (7u21). Java SE Embedded 7 Update 21 is based on Java Development Kit 7 Update 21 (JDK 7u21) and provides specific features and support for embedded systems.

To ensure that you have the most recent updates of the technical documents for Java SE Embedded, check the latest versions on the Java SE Embedded Product Documentation web site.

Platform Support

This release of Java SE Embedded 7 Update 21 was tested on Linux for ARM, Power Architecture and x86 systems. The requirements of these systems are specified at Java SE Embedded System Requirements. For ARM, testing was done on the v5, v6 and v7 architectures. Power Architecture systems based on e600 core and e500v2 core architectures were tested. Headless mode was tested on all systems; headful mode was tested on ARM v7.

Some of the information in this document describes support or issues concerning graphics, window managers, audio, and so forth, and therefore only applies to the headful release on ARMv7.

Java support on ARM is specific to the GNOME Desktop Environment version 1:2.30+7.

What's New in This Release

Java SE Embedded 7 Update 21 includes the new features of JDK 7u21. For more information on the cumulative changes of JDK 7u21 release, see Java SE 7 Update Release Notes.

Java Web Start and Java Plug-In are now removed from the Embedded bundles.

Known Limitations

ARM and PPC ReservedCodeCacheSize Maximum Value is 32 Megabytes

In Java SE Embedded 7 Update 21, the ARM and Power Architecture ReservedCodeCacheSize maximum value is 32 megabytes. The reason for ReservedCodeCacheSize limitation is an architecture restriction on branch offset. The limitation can be overcome by using a non-optimized sequence of instructions. However, this approach introduces a significant performance drop. Currently, JavaVM supports a maximum of 32 megabytes of ReservedCodeCacheSize for ARM and Power Architecture.

OpenGL Limitation

The headful version of Java SE Embedded 7 Update 21 on Linux ARM does not support the OpenGL acceleration pipeline for Java2D.

Garbage First Garbage Collector Not Supported

Java SE for Embedded 7 Update 21 does not support the Garbage First(G1) garbage collector.

Bug Fixes

Bug Database - In most cases, the bug ID number for each bug fixed is a link to the detailed bug report on the Bug Database web site. Bug Database enables you to file your own bug reports, add comments to existing bug reports, and vote for the bugs you consider most important.

Java SE Embedded 7 Update 21 is based on JDK 7u21 and contains fixes for security vulnerabilities. Refer to JDK 7u21 Release Notes for additional information on relevant bug fixes.

Comparison Between Java Development Kit (JDK) and Java SE Embedded

Java SE Embedded derives from JDK, but provides specific features and support for the embedded market on a limited set of supported platforms. The embedded-specific features and support include additional platforms, small footprint JREs (optional files removed), headless configurations, and memory optimizations.

All Java SE Embedded offerings are JDK compliant.

The Java SE Embedded is also available with "client" or "server" (JIT) compilers.

If the client version of the JRE is selected, user will receive a client JVM. In this case, only the -client option is available and using -server compiler option has the same effect as using the -client option.

Similarly, if a server version of the JRE is selected, only -server option is available and using the -client option has the same effect as using the -server option.

Note: Server Compiler support on ARM is introduced in Java SE Embedded 7 Update 2. See Server Compiler Technology section of Java SE Embedded 7 Update 2 Release Notes for support details.

For more information on functionality that is generally common to both JDK 7 and Java SE Embedded 7, including the Java language, HotSpot VM, Libraries and Tools, see the Java SE Documentation.

See also the JDK 7 Release Notes for release information on the JDK 7 platform.

For more information on functionality that is specific to Java SE Embedded 7, see SE Functionality Specific for Embedded.

Contact Us

For Java SE Embedded product inquiries, please contact the Java SE Embedded team.