Apple Java support
- Apple's Java implementation. Currently supports Java 5 and native "Aqua" look and feel on MacOS X.
- http://www.apple.com/macosx/features/java/

Novell JVM for NetWare.
- Offers Novell supported runtimes for NetWare.
- http://developer.novell.com/wiki/index.php/Novell_JVM_for_NetWare

Java(TM) 2 Platform, Standard Edition (Win32/Solaris/Linux)
- Sun's official page for the Java 2 Platform, Standard Edition (also known as JDK 1.2), with free downloads for Windows 95/98/NT/2000, Solaris and Linux.
- http://java.sun.com/javase/

Java 2 Platform - Sun Community Source Licensing
- Sun's source code for their implementations of the Java 2 Platform, Standard Edition, available free of charge.
- http://www.sun.com/software/communitysource/j2se/java2/index.xml

Java Technology Software from HP
- For Tru64 Unix, OpenVMS Alpha, Windows NT/Alpha and Linux/Alpha.
- http://h18012.www1.hp.com/java/

JRockit
- Highly scalable virtual machine with dynamic code optimization, available for WinNT/2000 and Linux. [Commercial]
- http://www.bea.com/framework.jsp?CNT=index.htm&FP=/content/products/jrockit

Java Technologies on SCO Systems
- JDKs for SCO systems.
- http://www.sco.com/developers/java/

Natural Bridge
- A system for statically compiling and linking JVM bytecode applications. It includes an optimizing ahead-of-time compiler, a linker and recompilation manager, an a
- http://www.naturalbridge.com/

Blackdown Java-Linux
- Blackdown's work formed the basis for Sun's official JDK for Linux-x86. Work continues on porting for other versions and architectures, including SPARC, PowerPC, and ARM; improvements to the x86 ports; and ports of extensions like JMF.
- http://www.blackdown.org/

MacOS Runtime for Java (MRJ)
- Apple's official MRJ.
- http://devworld.apple.com/java/

HP-UX Java Ports from HP
- Version 1.3 available.
- http://www.hp.com/products1/unix/java/

FreeBSD Java Project
- The official port of Sun's JDK to FreeBSD.
- http://www.freebsd.org/java/