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JVM
A Java virtual machine (JVM) is a virtual machine that enables a computer to run Java programs as well as programs written in other languages that are also compiled to Java bytecode. The JVM is detailed by a specification that formally describes what is required in a JVM implementation. Having a specification ensures interoperability of Java programs across different implementations so that program authors using the Java Development Kit (JDK) need not worry about idiosyncrasies of the underlying hardware platform. The JVM reference implementation is developed by the OpenJDK project as open source code and includes a JIT compiler called HotSpot. The commercially supported Java releases available from Oracle are based on the OpenJDK runtime. Eclipse OpenJ9 is another open source JVM for OpenJDK. JVM specification The Java virtual machine is an abstract (virtual) computer defined by a specification. It is a part of java runtime environment. The garbage-collection algorithm use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java (software Platform)
Java is a set of computer software and specifications developed by James Gosling at Sun Microsystems, which was later acquired by the Oracle Corporation, that provides a system for developing application software and deploying it in a cross-platform computing environment. Java is used in a wide variety of computing platforms from embedded devices and mobile phones to enterprise servers and supercomputers. Java applets, which are less common than standalone Java applications, were commonly run in secure, sandboxed environments to provide many features of native applications through being embedded in HTML pages. Writing in the Java programming language is the primary way to produce code that will be deployed as byte code in a Java virtual machine (JVM); byte code compilers are also available for other languages, including Ada, JavaScript, Python, and Ruby. In addition, several languages have been designed to run natively on the JVM, including Clojure, Groovy, and Scala. J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of JVM Languages
This list of JVM Languages comprises notable computer programming languages that are used to produce computer software that runs on the Java virtual machine (JVM). Some of these languages are interpreted by a Java program, and some are compiled to Java bytecode and JIT-compiled during execution as regular Java programs to improve performance. The JVM was initially designed to support only the programming language Java. However, as time passed, even more languages were adapted or designed to run on the Java platform. JVM languages High-profile languages As of September 2022, according to the TIOBE Index of the top 100 programming languages, the top JVM languages are: * Java (#3), a statically-typed object-oriented language * Scala (#33), a statically-typed object-oriented and functional programming language * Kotlin (#34, at one point at #27), a statically-typed language from JetBrains, the developers of IntelliJ IDEA and Google's preferred language for Android * Groovy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OpenJ9
Eclipse OpenJ9 (previously known as IBM J9) is a high performance, scalable, Java virtual machine (JVM) implementation that is fully compliant with the Java Virtual Machine Specification. OpenJ9 can be built from source, or can be used with prebuilt binaries available at the AdoptOpenJDK project for a number of platforms including Linux and Windows. OpenJ9 is also a core component of the IBM developer kit, which is embedded in many IBM middleware products, including WebSphere Application Server and Websphere Liberty. OpenJ9 is also a component of Open Liberty. Extensive configuration options ensure that the JVM can be tuned to satisfy the requirements of a wide range of Java applications, from complex enterprise applications that run on mainframe hardware to short-lived applications that run on container-based cloud services. cloud statement: The design of the J9 VM has been aimed at portability to different platforms, as well as scaling from mobile phones all the way to I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Bytecode
In computing, Java bytecode is the bytecode-structured instruction set of the Java virtual machine (JVM), a virtual machine that enables a computer to run programs written in the Java programming language and several other programming languages, see List of JVM languages. Relation to Java A Java programmer does not need to be aware of or understand Java bytecode at all. However, as suggested in the IBM developerWorks journal, "Understanding bytecode and what bytecode is likely to be generated by a Java compiler helps the Java programmer in the same way that knowledge of assembly helps the C or C++ programmer." Instruction set architecture The JVM is both a stack machine and a register machine. Each frame for a method call has an "operand stack" and an array of "local variables". The operand stack is used for operands to computations and for receiving the return value of a called method, while local variables serve the same purpose as registers and are also used to pass me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HotSpot (virtual Machine)
HotSpot, released as Java HotSpot Performance Engine, is a Java virtual machine for desktop and server computers, developed by Sun Microsystems and now maintained and distributed by Oracle Corporation. It features improved performance via methods such as just-in-time compilation and adaptive optimization. History The Java HotSpot Performance Engine was released on April 27, 1999, built on technologies from an implementation of the programming language Smalltalk named Strongtalk, originally developed by Longview Technologies, which traded as Animorphic. The Longview virtual machine was based on the Self virtual machine, with an interpreter replacing the fast-and-dumb first compiler. When Sun cancelled the Self project, two key people, Urs Hölzle and Lars Bak left Sun to start Longview. In 1997, Sun Microsystems purchased Animorphic. Shortly after acquiring Animorphic, Sun decided to write a new just-in-time (JIT) compiler for the Java virtual machine. This new compiler w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JRockit
JRockit was a proprietary Java virtual machine (JVM) originally developed by Appeal Virtual Machines, acquired by BEA Systems in 2002, and became part of Oracle Fusion Middleware as part of acquisition of BEA Systems in 2008. The JRockit code base was discontinued by Oracle, with some features being integrated into the HotSpot virtual machine as part of the mainline development of the Java platform. JRockit only ever supported Java 6, which is now considered an obsolete release. History Following the finalization of the acquisition of Sun Microsystems, Oracle announced in JavaOne 2010 that the best features of JRockit would be implemented in OpenJDK. In May 2011, Oracle announced that JRockit has become free, and confirmed the plan to port JRockit features on OpenJDK OpenJDK (Open Java Development Kit) is a free and open-source implementation of the Java Platform, Standard Edition (Java SE). It is the result of an effort Sun Microsystems began in 2006. The implementation i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OpenJDK
OpenJDK (Open Java Development Kit) is a free and open-source implementation of the Java Platform, Standard Edition (Java SE). It is the result of an effort Sun Microsystems began in 2006. The implementation is licensed under the GPL-2.0-only with a linking exception. Were it not for the GPL linking exception, components that linked to the Java class library would be subject to the terms of the GPL license. OpenJDK is the official reference implementation of Java SE since version 7. Components The OpenJDK project produces a number of components: most importantly the virtual machine ( HotSpot), the Java Class Library and the Java compiler (javac). The web-browser plugin and Web Start, which form part of Oracle Java, are not included in OpenJDK. Sun previously indicated that they would try to open-source these components, but neither Sun nor Oracle have done so. The only currently available free plugin and Web Start implementations are those provided by IcedTea. OpenJDK 9+ su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Development Kit
The Java Development Kit (JDK) is a distribution of Java Technology by Oracle Corporation. It implements the Java Language Specification (JLS) and the Java Virtual Machine Specification (JVMS) and provides the Standard Edition (SE) of the Java Application Programming Interface (API). It is derivative of the community driven OpenJDK which Oracle stewards. It provides software for working with Java applications. Examples of included software are the virtual machine, a compiler, performance monitoring tools, a debugger, and other utilities that Oracle considers useful for a Java programmer. Oracle have released the current version of the software under the Oracle No-Fee Terms and Conditions (NFTC) license. Oracle release binaries for the x86-64 architecture for Windows, macOS, and Linux based operating systems, and for the aarch64 architecture for macOS and Linux. Previous versions have supported the Oracle Solaris operating system and SPARC architecture. Oracle's primary implemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class (file Format)
A Java class file is a file (with the filename extension) containing Java bytecode that can be executed on the Java Virtual Machine (JVM). A Java class file is usually produced by a Java compiler from Java programming language source files ( files) containing Java classes (alternatively, other JVM languages can also be used to create class files). If a source file has more than one class, each class is compiled into a separate class file. JVMs are available for many platforms, and a class file compiled on one platform will execute on a JVM of another platform. This makes Java applications platform-independent. History On 11 December 2006, the class file format was modified under Java Specification Request (JSR) 202. File layout and structure Sections There are 10 basic sections to the Java class file structure: * Magic Number: 0xCAFEBABE * Version of Class File Format: the minor and major versions of the class file * Constant Pool: Pool of constants for the class * Access F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sun Microsystems
Sun Microsystems, Inc. (Sun for short) was an American technology company that sold computers, computer components, software, and information technology services and created the Java programming language, the Solaris operating system, ZFS, the Network File System (NFS), and SPARC microprocessors. Sun contributed significantly to the evolution of several key computing technologies, among them Unix, RISC processors, thin client computing, and virtualized computing. Notable Sun acquisitions include Cray Business Systems Division, Storagetek, and ''Innotek GmbH'', creators of VirtualBox. Sun was founded on February 24, 1982. At its height, the Sun headquarters were in Santa Clara, California (part of Silicon Valley), on the former west campus of the Agnews Developmental Center. Sun products included computer servers and workstations built on its own RISC-based SPARC processor architecture, as well as on x86-based AMD Opteron and Intel Xeon processors. Sun also developed its own ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Platform, Standard Edition
Java Platform, Standard Edition (Java SE) is a computing platform for development and deployment of portable code for desktop and server environments. Java SE was formerly known as Java 2 Platform, Standard Edition (J2SE). The platform uses Java programming language and is part of the Java software-platform family. Java SE defines a range of general-purpose APIs—such as Java APIs for the Java Class Library—and also includes the Java Language Specification and the Java Virtual Machine Specification. OpenJDK is the official reference implementation since version 7. Nomenclature, standards and specifications The platform was known as ''Java 2 Platform, Standard Edition'' or ''J2SE'' from version 1.2, until the name was changed to ''Java Platform, Standard Edition'' or ''Java SE'' in version 1.5. The "SE" is used to distinguish the base platform from the Enterprise Edition (Java EE) and Micro Edition (Java ME) platforms. The "2" was originally intended to emphasize the maj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JIT Compiler
In computing, just-in-time (JIT) compilation (also dynamic translation or run-time compilations) is a way of executing computer code that involves compilation during execution of a program (at run time) rather than before execution. This may consist of source code translation but is more commonly bytecode translation to machine code, which is then executed directly. A system implementing a JIT compiler typically continuously analyses the code being executed and identifies parts of the code where the speedup gained from compilation or recompilation would outweigh the overhead of compiling that code. JIT compilation is a combination of the two traditional approaches to translation to machine code—ahead-of-time compilation (AOT), and interpretation—and combines some advantages and drawbacks of both. Roughly, JIT compilation combines the speed of compiled code with the flexibility of interpretation, with the overhead of an interpreter and the additional overhead of compil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
