Java

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Java Virtual Machines (JVM) options for Linux on POWER:

Basically, the following different JVM implementations are available for Linux on POWER:

  • IBM JVM
  • Sun JVM provided by Blackdown
  • GCJ and GNU Classpath
  • Sun Embedded J2SE

Both JVM implementations are available for different versions of the Java APIs (the latest being in that order v1.5.0, v1.4.2, v1.3.1). They do, however, differ in certain areas which makes it sometimes difficult for Java applications to simply swap the underlying JVM.

The IBM Java Developer Kits:

The IBM Center for Java Technology Development provides Developer Kits for creating and testing Java 2 Platform, Standard Edition applets and applications on some of IBM's most popular platforms. The latest information can be found at the following URL: http://www-128.ibm.com/developerworks/java/jdk/

The following three links also provide helpful information:

For Linux on POWER the following recent Linux distributions are officially supported (details can be found at the link Tested Linux platforms and distributions mentioned above):

  1. Red Hat Enterprise Linux Advanced Server 3 (RHEL3)
  2. Red Hat Enterprise Linux Advanced Server 4 (RHEL4)
  3. SUSE Linux Enterprise Server 9 (SLES9)

Remarks:

  1. Please notice that for different IBM Java versions, e.g., v1.4.2, also several Service Releases (SR) are available! The latest SR is typically available only online and not always incorporated into the latest Linux distribution.
  2. IBM Java v1.5.0 has just been released and is not yet incorporated in any officially supported (please see above) Linux distribution.

The Sun Java Developer Kits - as provided by Blackdown:

Sun actually does not provide a JVM implementation for Linux on POWER but this is provided by the Blackdown.org Linux developer community and should thus be more properly named Blackdown Java. Their main web pages can be found at: http://www.blackdown.org/

The latest status information about the Java2 Blackdown releases can be found at: http://www.blackdown.org/java-linux/java2-status/

Unfortunately, for Linux on POWER the latest released JVM implementation by Blackdown is v1.3.1, no later releases are currently available !

Remarks:

  1. If Java2 API v1.4.x is required, the only currently available JVM is the IBM JVM implementation, no Sun JVM implementation is available !
  2. Blackdown.org mentions on their web pages that they are porting Java2 v1.5 to the following platforms: x86, AMD64, SPARC and PPC (please see the following URL: http://www.blackdown.org/java-linux/java2-status/j2se1.5-status.html.
    However, this information dates back already to November 22nd, 2004 and no further official information since then is available.

GCJ and GNU Classpath

These projects provide a free and open source Java environment which includes a tool suite and execution environment that is capable of building and running many useful programs that are written in the Java programming language. It consists of the following components:

  1. GCJ is a portable, optimizing, ahead-of-time compiler for the Java Programming Language.
  2. GNU Classpath, Essential Libraries for Java, is a GNU project to create free core class libraries for use with virtual machines and compilers for the Java programming language.

Details can be found here:

Sun Embedded J2SE

In April 2006 Sun has made their Java Platform, Standard Edition (Java SE) v1.4.2 for Embedded Use available as an evaluation release.

From Sun's website:
Java SE for PowerPC Now Available! Java SE for Embedded now runs on PowerPC for Linux. Featuring Sun's award-winning HotSpot JVM with custom features for embedded devices including headless support and low memory handling. Get the evaluation release and check it out.

URL: http://java.sun.com/j2se/embedded/

Remarks:

  • A survey has to be completed before the download of the evaluation package can start.
  • A quick test on SLES9 SP3, RHEL4 Update 3, Debian Sarge, Fedora Core 4 and openSUSE 10.0 has shown it works also on these platforms despite being announced for embedded systems only.
  • This current evaluation release has the following drawbacks, however:
    • currently in early access stage.
    • only has JRE, no JDK.
    • 32-bit only, no 64-bit support.

Current status Linux distributions (latest versions available):

  • SLES9 Service Pack 3 currently ships:
    • Sun Java v1.3.1 (JRE and JDK)
    • IBM Java v1.4.2 SR2 (JRE and JDK)
  • RHEL3 Quaterly Update 6 currently ships no Java, download from the links above!
  • RHEL4 Quarterly Update 3 currently ships no Java, download from the links above!
  • openSUSE 10.0 currently ships no Java, download from the links above!
  • Fedora Core 4
    • includes and integrates the latest 4.0 version of GNU Compiler Collection which has a rewritten optimisation infrastructure and improved support for a native Free Java software stack. This includes parts of OpenOffice.org 2.0, Eclipse, and Apache Jakarta, among others.
    • another option is to download from the links above!
  • Fedora Core 5
    • includes a free and open source Java environment called java-gcj-compat. java-gcj-compat includes a tool suite and execution environment that is capable of building and running many useful programs that are written in the Java programming language. Java is a trademark of Sun Microsystems. java-gcj-compat is an entirely free software stack that is not Java, but may run Java software.
    • another option is to download from the links above!
  • Debian Sarge (3.1) offers the 3.4 version of the GNU Compiler Collection Java implementation together with the Java Classpath Java libraries.
  • Gentoo 2006.0 offers a choice of the following JREs and JDKs:
    • blackdown-jre and blackdown-jdk, the Blackdown Java Kit
    • ibm-jre-bin and ibm-jdk-bin, the IBM Java Kit


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