免费和开源的 Java 虚拟机
AegisVM (inactive since 2004).
Apache Harmony — supports several architectures and systems. Discontinued November 2011. Apache License 2.0.
Avian — A small, easily embeddable Java VM and classpath using just-in-time compilation.
Azul Zulu — is an OpenJDK build supported by Azul Systems. It is open source and free to download. The initial release ran on Windows Server 2008 R2 and 2012 on the Windows Azure Cloud. Release in January 21, 2014 supports multiple versions of Linux as well as Amazon Web Services, Rackspace and various hypervisors. Also added an Enterprise version with subscription support available. In June 2014 Mac OS X support was added. [1]
Bck2Brwsr — small JVM capable to boot fast and run in 100% of modern browsers including those that have no special support for Java. Last release in September, 2013.
CACAO — uses GNU Classpath, supports multiple architectures. GPL. 1.6.0 released September 4, 2012.
GCJ the GCC Java compiler, that compiles either to bytecode or to native machine code. The product is currently in maintenance mode.
HaikuVM, for Atmel AVRs (Arduino) and other micros using the leJOS runtime.
HotSpot, the primary reference Java VM implementation.
IcedTea — has the only working free software Java Web browser plugin. GPL+linking exception.
IKVM.NET — Java for Mono and the Microsoft .NET Framework. Uses OpenJDK. Zlib License.
Jamiga — for the Amiga platform. Depends on GNU Classpath. GPL.
JamVM — Developed to be an extremely small virtual machine compared to others. Designed to use GNU Classpath. Supports several architectures. GPL.
Jaos — Java on Active Object System. Uses GNU Classpath as a standard library. Unmaintained.
Jato VM — uses GNU Classpath. GPL.
JC — Converts class files from byte-code into C. Uses Soot and GNU Classpath. GNU Library or LGPL licenses.
Jelatine JVM
JESSICA (Java-Enabled Single-System-Image Computing Architecture).
Jikes RVM (Jikes Research Virtual Machine) — Research project. PPC and IA-32. Supports Apache Harmony and GNU Classpath libraries. Eclipse Public License.
JNode — operating system. Version 0.2.8 released on January 29, 2009. LGPL.
JOP — Hardware implementation of the JVM. GPL 3.
Juice — JavaME experimental JVM developed to run on the NUXI operating system.
Jupiter — Uses Boehm garbage collector and GNU Classpath. GPL. Unmaintained.
JwiK Open Source Java VM for 8bit micro for wireless applications.
JX (operating system) — GPL. Version 0.1.1 released on October 10, 2007.
Kaffe — Uses GNU Classpath. GPL. 1.1.9 released on February 26, 2008.
leDos real-mode x86 JVM running on MS-DOS. MPL.
leJOS — Robotics suite, a firmware replacement for Lego Mindstorms programmable bricks, provides a Java programming environment for the Lego Mindstorms RCX and NXT robots.
MateVM — An experimental JIT implemented in Haskell. GPL.
Maxine — meta-circular open source research VM from Oracle Labs.
Mika VM — intended for use in embedded devices. Cross-platform. BSD-style licence.
miniMV (from UABC-Tij for embedded systems and Wireless Sensor network devices)[citation needed].
Mysaifu (Windows CE/Windows Mobile) — the only open source Java SE-compatible JVM still in development for PocketPC devices. GPL 2.
NanoVM — developed to run on the Atmel AVR ATmega8 used in the Asuro Robot, can be ported to other AVR-based systems.
RoboVM — AOT compiler and runtime which targets iOS, Mac OS X and Linux. Largely based on Android‘s runtime.
SableVM — First free software JVM to support JVDMI and JDWP. Makes use of GNU Classpath. LGPL. Version 1.13 released on March 30, 2007.
Squawk virtual machine — A Java ME VM for embedded systems and small devices. Cross-Platform. GPL.
SuperWaba — Java-like virtual machine for portable devices. GPL. Discontinued, succeeded by TotalCross.
TakaTuka — for wireless sensor network devices. GPL.
TinyVM.
VM02 a Java-compatible environment for the Apple II series of computers.
VMkit of LLVM.
Wonka VM — Developed to run on Acunia‘s ARM-based hardware. Some code drawn from GNU Classpath. BSD-style licence. No longer under active development, superseded by Mika VM.


收费虚拟机实现
Azul Zing JVM a fully compliant Java Virtual Machine based on HotSpot that uses the Azul C4 (Continuously Concurrent Compacting Collector) garbage collector. Supports memory heaps of 100s of GB without GC pauses and is able to grow and shrink the heap based on load.
CEE-J is a clean room implementation of Sun‘s Java technology, Skelmir is not a licensee of Oracle.
Excelsior JET is a licensed Java SE implementation with AOT compiler
Hewlett-Packard, Java for HP-UX, OpenVMS, Tru64 and Reliant (Tandem) UNIX platforms
J9 (IBM), for Windows, AIX, Linux (x86 and PPC), MVS, OS/400, Pocket PC, z/OS
"Classic JVM" for IBM OS/400 (superseded by J9)
Imsys AB provides their SNAP (Simple Network Application Platform) JVM running on their proprietary IM1000 and IM3000 microprocessors that feature microcode execution of Java byte codes.
Apogee provides embedded Java using IBM J9 and Apache Harmony Class Library for X86, ARM, MIPS, PowerPC running on Linux, LynxOS, WinCE.
JBed, (Esmertec) is an embedded Java with multimedia capabilities
JamaicaVM, (aicas) is a hard real-time Java VM for embedded systems
JBlend, (Aplix) is a Java ME implementation装修效果图
Jinitiator, developed by Oracle before they purchased Sun. Designed to improve support for Oracle Forms in web sites.
JRockit (originally from Appeal Virtual Machines) acquired by Oracle for Linux, Windows and Solaris
Mac OS Runtime for Java (MRJ)http://www.bizhizu.cn/zhuangxiu/?
MicroJvm (IS2T - Industrial Smart Software Technology) Wide range of virtual machines dedicated to embedded systems (including hard real-time constrained systems), ARM7, ARM9, AVR, AVR32, PPC, MIPS, ...
Microsoft Java Virtual Machine (discontinued in 2001)
OJVM (also known as "JServer") from Oracle Corporation
PERC (Aonix/Atego) is a real time Java for embedded. Aonix is not a licensee of Oracle.
SAPJVM (SAP) is a licensed and modified SUN JVM ported to all supported platforms of SAP NetWeaver, started as Java 5, in the meantime Java 6 compatible (Windows i386, x64, IA-64; Linux x86, IA-64, PowerPC; AIX PowerPC; HP-UX SPARC IA-64; Solaris SPARC x86-64; i5/OS PowerPC)
Waratek CloudVM for Java A multitenant JVM that allows per-tenant isolation, metering and resource control


比较偏门的专有虚拟机实现
Blackdown Java was a licensed port to Linux of the reference SunSoft implementation. It was discontinued in 2007, after OpenJDK became available.
C virtual machine (CVM, from Sun), supports C
Gemstone - modified for Java EE features (application DBMS)
Golden Code Development (EComStation and OS/2 port of Java RTE and SDK for Java SE v1.4.1_07)
HP ChaiVM and MicrochaiVM
Intent (Tao Group)
Novell, India.
NSIcom CrE-ME
PreonVM (Virtenio) A VM for embedded systems and small devices.