Kaffe
Encyclopedia
Kaffe is a clean room design
of a Java Virtual Machine
. It comes with a subset of the Java Platform, Standard Edition
(Java SE), Java API, and tool
s needed to provide a Java runtime environment. Like most other Free Java virtual machines, Kaffe uses GNU Classpath
as its class library
.
Kaffe, first released in 1996, was the original open-source Java implementation. Initially developed as part of another project, it grew so popular that developers Tim Wilkinson and Peter Mehlitz founded Transvirtual Technologies, Inc. with Kaffe as the company's flagship product. In July 1998, Transvirtual released Kaffe OpenVM under a GNU General Public License
. Now it is developed by a world-wide team of programmers. Beside the mailing list, the developers can often be reached via IRC in the #kaffe channel on irc.freenode.net.
Kaffe is a lean and portable virtual machine
, although it is significantly slower than commercial implementations. When compared to the reference implementation of the Java Virtual Machine written by Sun Microsystems
, Kaffe is significantly smaller; it thus appeals to embedded system
developers
. It comes with just-in-time
compilers for many of the CPU architectures, and has been port
ed to more than 70 system platforms in total. It runs on devices ranging from embedded
SuperH
devices to IBM zSeries mainframe computer
s, and it will even run on a PlayStation 2
.
Unlike other implementations, in the past Kaffe used GNU Multi-Precision Library
(GMP) to support arbitrary precision arithmetics. This feature has been removed from release 1.1.9, causing protests from people that claim they used Kaffe for the sole reason GMP arithmetic being faster than the typical pure java implementation, available in other distributions. The capability was removed to reduce the maintenance work, expecting that interested people will integrate GMP support into GNU Classpath
or OpenJDK
. Subsequently GNU Classpath introduced GMP support in version 0.98.
Clean room design
Clean room design is the method of copying a design by reverse engineering and then recreating it without infringing any of the copyrights and trade secrets associated with the original design. Clean room design is useful as a defense against copyright and trade secret infringement because it...
of a Java Virtual Machine
Java Virtual Machine
A Java virtual machine is a virtual machine capable of executing Java bytecode. It is the code execution component of the Java software platform. Sun Microsystems stated that there are over 4.5 billion JVM-enabled devices.-Overview:...
. It comes with a subset of the Java Platform, Standard Edition
Java Platform, Standard Edition
Java Platform, Standard Edition or Java SE is a widely used platform for programming in the Java language. It is the Java Platform used to deploy portable applications for general use...
(Java SE), Java API, and tool
Programming tool
A programming tool or software development tool is a program or application that software developers use to create, debug, maintain, or otherwise support other programs and applications...
s needed to provide a Java runtime environment. Like most other Free Java virtual machines, Kaffe uses GNU Classpath
GNU Classpath
GNU Classpath is a project aiming to create a free software implementation of the standard class library for the Java programming language. Despite the massive size of the library to be created, the majority of the task is already done, including Swing, CORBA, and other major parts. The Classpath...
as its class library
Java Class Library
The Java Class Library is a set of dynamically loadable libraries that Java applications can call at run time. Because the Java Platform is not dependent on any specific operating system, applications cannot rely on any of the existing libraries...
.
Kaffe, first released in 1996, was the original open-source Java implementation. Initially developed as part of another project, it grew so popular that developers Tim Wilkinson and Peter Mehlitz founded Transvirtual Technologies, Inc. with Kaffe as the company's flagship product. In July 1998, Transvirtual released Kaffe OpenVM under a GNU General Public License
GNU General Public License
The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....
. Now it is developed by a world-wide team of programmers. Beside the mailing list, the developers can often be reached via IRC in the #kaffe channel on irc.freenode.net.
Kaffe is a lean and portable virtual machine
Virtual machine
A virtual machine is a "completely isolated guest operating system installation within a normal host operating system". Modern virtual machines are implemented with either software emulation or hardware virtualization or both together.-VM Definitions:A virtual machine is a software...
, although it is significantly slower than commercial implementations. When compared to the reference implementation of the Java Virtual Machine written by Sun Microsystems
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...
, Kaffe is significantly smaller; it thus appeals to embedded system
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
developers
Programmer
A programmer, computer programmer or coder is someone who writes computer software. The term computer programmer can refer to a specialist in one area of computer programming or to a generalist who writes code for many kinds of software. One who practices or professes a formal approach to...
. It comes with just-in-time
Just-in-time compilation
In computing, just-in-time compilation , also known as dynamic translation, is a method to improve the runtime performance of computer programs. Historically, computer programs had two modes of runtime operation, either interpreted or static compilation...
compilers for many of the CPU architectures, and has been port
Porting
In computer science, porting is the process of adapting software so that an executable program can be created for a computing environment that is different from the one for which it was originally designed...
ed to more than 70 system platforms in total. It runs on devices ranging from embedded
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
SuperH
SuperH
SuperH is a 32-bit reduced instruction set computer instruction set architecture developed by Hitachi. It is implemented by microcontrollers and microprocessors for embedded systems....
devices to IBM zSeries mainframe computer
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...
s, and it will even run on a PlayStation 2
PlayStation 2
The PlayStation 2 is a sixth-generation video game console manufactured by Sony as part of the PlayStation series. Its development was announced in March 1999 and it was first released on March 4, 2000, in Japan...
.
Unlike other implementations, in the past Kaffe used GNU Multi-Precision Library
GNU Multi-Precision Library
The GNU Multiple Precision Arithmetic Library, also known as GMP, is a free library for arbitrary-precision arithmetic, operating on signed integers, rational numbers, and floating point numbers...
(GMP) to support arbitrary precision arithmetics. This feature has been removed from release 1.1.9, causing protests from people that claim they used Kaffe for the sole reason GMP arithmetic being faster than the typical pure java implementation, available in other distributions. The capability was removed to reduce the maintenance work, expecting that interested people will integrate GMP support into GNU Classpath
GNU Classpath
GNU Classpath is a project aiming to create a free software implementation of the standard class library for the Java programming language. Despite the massive size of the library to be created, the majority of the task is already done, including Swing, CORBA, and other major parts. The Classpath...
or OpenJDK
OpenJDK
OpenJDK is a free and open source implementation of the Java programming language. It is the result of an effort Sun Microsystems began in 2006...
. Subsequently GNU Classpath introduced GMP support in version 0.98.
See also
- List of Java virtual machines
- GNU ClasspathGNU ClasspathGNU Classpath is a project aiming to create a free software implementation of the standard class library for the Java programming language. Despite the massive size of the library to be created, the majority of the task is already done, including Swing, CORBA, and other major parts. The Classpath...
- Free Java implementationsFree Java implementationsFree Java implementations are software projects that implement Oracle's Java technologies and are distributed under free software licences, thus making them free software...