Release Notes


Java™ SE for Embedded 6 Runtime Environment

Apr 21, 2011

This document summarizes the functionality and issues of Java SE for Embedded 6. Java SE for Embedded 6 Update 25 is based on the Java Platform 6 Update 25, Standard Edition (Java SE 6 Update 25) 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 for Embedded, check the latest versions on the Java SE for Embedded Product Documentation web site.

Contents

Platform Support

What's New in This Release

Known Limitation

Bug Fixes

Comparisons with Standard Java SE

How to Enable Java Plug-In

Release Notes for Previous Releases

Contact Us


Platform Support

This release of Java SE for Embedded 6 was tested on Linux for ARM, Power Architecture and x86 systems. The requirements of these systems are specified at Java SE for 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 ARM v7 headful release.

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What's New in This Release

The full HPROF functionality of the Java SE 6 JDK has been added to Java SE for Embedded 6 Update 25.
Detailed HPROF information can be found at:

The following is a brief summary:

Invoking HPROF

HPROF is invoked as follows:

java -agentlib:hprof[=option1,option2,...] Main

where Main is the name of the embedded application Java class being targeted for profiling. The options (option1,option2,...) are either single tokens or settings of the form parameter=value.

Usage Example

The following is a typical usage example:

java -agentlib:hprof=heap=dump,format=b Main

Help on all the possible HPROF options can be obtained as follows:

java -agentlib:hprof=help

Analysis

The analysis tool jhat is often used to interpret the data in the output file generated by HPROF. This tool is provided only in the Java SE JDK. It's not provided in the Java SE JRE nor in the Java SE for Embedded. However, the format of the HPROF file is platform-independent, hence jhat from any Java SE 6 JDK on any platform can be used to analyze HPROF files generated by Java SE for Embedded 6 Update 25. For further details on jhat, see jhat.

For more info on the cumulative changes of Java SE 6 releases, see Java SE Update Release Notes.

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Known Limitation


ARM and PPC ReservedCodeCacheSize Maximum Value is 32 Megabytes

In Java SE for Embedded 6 Update 25, the ARM and PPC 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 PPC.


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 (Bug Parade) 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.

The following table lists the bug fixes in Java SE for Embedded 6 Update 25.

Bug ID Category Sub-Category Description
7002592  java embedded Hprof Profile not supported by Java SE Embedded JRE
7011262  java embedded ARM: Division by power of two constants fails for negative numbers

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Comparisons with Standard Java SE

Java SE for Embedded derives from Java SE. It can support the same platforms and functionality as Java SE. In addition, Java SE for Embedded provides specific features and support for the embedded market. The embedded-specific features and support include additional platforms, small footprint JREs (optional files removed), headless configurations, and memory optimizations.

All Java SE for Embedded offerings are Java SE compliant.

Java SE for Embedded provides only the 32-bit "client" version of the Java virtual machine; the 64-bit version is not supported, and using the -server option has no effect.

For more information on functionality that is generally common to both Standard Java SE 6 and Java SE for Embedded 6, including the Java language, HotSpot VM, Libraries and Tools, see the Java SE Documentation.

See also the Java SE 6 Release Notes for release information on the Java SE 6 platform.

For more information on functionality that is specific to Java SE for Embedded 6, see SE Functionality Specific for Embedded.

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How to Enable Java Plug-In

The headful version of Java SE for Embedded 6 on ARM v6/v7 supports the Java™ Plug-in technology. We have verified that it works with the CoolFox web browser; it likely works with the FireFox web browser (on which CoolFox is based) as well. Mozilla's Gecko rendering engine version 1.9.0 FCS or later is required. Non-Mozilla web browsers, including the WebKit rendering engine (used in some non-Mozilla web browsers), are not supported at the time of this writing.

It is important to realize that a symbolic link needs to be created in order to get the Java Plug-in to work. This link points from the browser's plugins directory to the Java Plug-in shared library included in the JRE and it can be created with the following command from a shell:

ln -s <JAVA_HOME>/lib/arm/libnpjp2.so <MOZILLA_DIR>/plugins/libnpjp2.so

In the above command, <JAVA_HOME> represents the directory where you installed the headful Java SE for Embedded 6 bundle (for example, /usr/java/ejre1.6.0_25), and <MOZILLA_DIR> represents the directory where you installed your web browser (for example, /usr/lib/mozilla).

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Release Notes for Previous Releases

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Contact Us

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

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