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60-424: Gosu can serve as a scripting language, having free-form Program types (.gsp files) for scripting as well as statically verified Template files (.gst files). Gosu can optionally execute these and all other types directly from source without precompilation, which also distinguishes it from other static languages. Gosu began in 2002 as a scripting language called GScript at Guidewire Software. It has been described as

120-461: A Java variant that attempts to make useful improvements while retaining the fundamental utility and compatibility with Java. It was used to configure business logic in Guidewire's applications and was more of a simple rule definition language. In its original incarnation it followed ECMAScript guidelines. Guidewire enhanced the scripting language over the next 8 years, and released Gosu 0.7 beta to

180-483: A String to print itself: The combination of closures and enhancements provide a powerful way of coding with Collections. The overhead of Java streams is unnecessary with Gosu: This general-purpose programming language is used primarily in Guidewire Software 's commercial products. Java (programming language) Java is a high-level , class-based , object-oriented programming language that

240-706: A lawsuit against Google shortly after that for using Java inside the Android SDK (see the Android section). On April 2, 2010, James Gosling resigned from Oracle . In January 2016, Oracle announced that Java run-time environments based on JDK 9 will discontinue the browser plugin. Java software runs on everything from laptops to data centers , game consoles to scientific supercomputers . Oracle (and others) highly recommend uninstalling outdated and unsupported versions of Java, due to unresolved security issues in older versions. There were five primary goals in creating

300-478: A number of other standard servlet classes available, for example for WebSocket communication. The Java servlet API has to some extent been superseded (but still used under the hood) by two standard Java technologies for web services: Typical implementations of these APIs on Application Servers or Servlet Containers use a standard servlet for handling all interactions with the HTTP requests and responses that delegate to

360-440: A small portion of code to which Sun did not hold the copyright. Sun's vice-president Rich Green said that Sun's ideal role with regard to Java was as an evangelist . Following Oracle Corporation 's acquisition of Sun Microsystems in 2009–10, Oracle has described itself as the steward of Java technology with a relentless commitment to fostering a community of participation and transparency. This did not prevent Oracle from filing

420-566: A subject of controversy during the 2010s. The class library contains features such as: Javadoc is a comprehensive documentation system, created by Sun Microsystems . It provides developers with an organized system for documenting their code. Javadoc comments have an extra asterisk at the beginning, i.e. the delimiters are /** and */ , whereas the normal multi-line comments in Java are delimited by /* and */ , and single-line comments start with // . Java bytecode Java bytecode

480-401: A suffix of the form _ n , where n is a number from 0–3 for load and store . The maximum n for const differs by type. The const instructions push a value of the specified type onto the stack. For example, iconst_5 will push an integer (32 bit value) with the value 5 onto the stack, while dconst_1 will push a double (64 bit floating point value) with the value 1 onto

540-510: Is a necessary ingredient toward best of breed tooling via static program analysis , rich parser feedback, code completion , deterministic refactoring, usage analysis, navigation, and the like. Gosu follows a syntax resembling a combination of other languages. For instance, declarations follow more along the lines of Pascal with name-first grammar. Gosu classes can have functions, fields, properties, and inner classes as members. Nominal inheritance and composition via delegation are built into

600-619: Is actually two compilers in one; and with GraalVM (included in e.g. Java 11, but removed as of Java 16) allowing tiered compilation . Java itself is platform-independent and is adapted to the particular platform it is to run on by a Java virtual machine (JVM), which translates the Java bytecode into the platform's machine language. Programs written in Java have a reputation for being slower and requiring more memory than those written in C++ . However, Java programs' execution speed improved significantly with

660-434: 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 method arguments. The maximum size of the operand stack and local variable array, computed by

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720-440: Is composed of one byte that represents the opcode , along with zero or more bytes for operands. Of the 256 possible byte-long opcodes , as of 2015 , 202 are in use (~79%), 51 are reserved for future use (~20%), and 3 instructions (~1%) are permanently reserved for JVM implementations to use. Two of these ( impdep1 and impdep2 ) are to provide traps for implementation-specific software and hardware, respectively. The third

780-411: Is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers write once, run anywhere ( WORA ), meaning that compiled Java code can run on all platforms that support Java without the need to recompile. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of

840-409: Is implicitly allocated on the stack or explicitly allocated and deallocated from the heap . In the latter case, the responsibility of managing memory resides with the programmer. If the program does not deallocate an object, a memory leak occurs. If the program attempts to access or deallocate memory that has already been deallocated, the result is undefined and difficult to predict, and the program

900-623: Is insufficient free memory on the heap to allocate a new object; this can cause a program to stall momentarily. Explicit memory management is not possible in Java. Java does not support C/C++ style pointer arithmetic , where object addresses can be arithmetically manipulated (e.g. by adding or subtracting an offset). This allows the garbage collector to relocate referenced objects and ensures type safety and security. As in C++ and some other object-oriented languages, variables of Java's primitive data types are either stored directly in fields (for objects) or on

960-431: Is its Open Type System, which allows the language to be easily extended to provide compile-time checking and IDE awareness of information that is typically checked only at runtime in most other languages. Enhancements let you add additional functions and properties to other types, including built-in Java types such as String, List, etc. This example demonstrates adding a print() function to java.lang.String. Now you can tell

1020-399: Is likely to become unstable or crash. This can be partially remedied by the use of smart pointers , but these add overhead and complexity. Garbage collection does not prevent logical memory leaks, i.e. those where the memory is still referenced but never used. Garbage collection may happen at any time. Ideally, it will occur when a program is idle. It is guaranteed to be triggered if there

1080-420: Is no longer needed, typically when objects that are no longer needed are stored in containers that are still in use. If methods for a non-existent object are called, a null pointer exception is thrown. One of the ideas behind Java's automatic memory management model is that programmers can be spared the burden of having to perform manual memory management. In some languages, memory for the creation of objects

1140-528: Is supported for interfaces . Java uses comments similar to those of C++. There are three different styles of comments: a single line style marked with two slashes ( // ), a multiple line style opened with /* and closed with */ , and the Javadoc commenting style opened with /** and closed with */ . The Javadoc style of commenting allows the user to run the Javadoc executable to create documentation for

1200-444: Is the instruction set of the Java virtual machine (JVM), the language to which Java and other JVM-compatible source code is compiled . Each instruction is represented by a single byte , hence the name bytecode , making it a compact form of data . Due to the nature of bytecode, a Java bytecode program is runnable on any machine with a compatible JVM; without the lengthy process of compiling from source code. Java bytecode

1260-447: Is the latest version (Java 22, and 20 are no longer maintained). Java 8, 11, 17, and 21 are previous LTS versions still officially supported. James Gosling , Mike Sheridan, and Patrick Naughton initiated the Java language project in June 1991. Java was originally designed for interactive television, but it was too advanced for the digital cable television industry at the time. The language

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1320-466: Is used at runtime either interpreted by a JVM or compiled to machine code via just-in-time (JIT) compilation and run as a native application. As Java bytecode is designed for a cross-platform compatibility and security, a Java bytecode application tends to run consistently across various hardware and software configurations. In general, a Java programmer does not need to understand Java bytecode or even be aware of it. However, as suggested in

1380-499: Is used for debuggers to implement breakpoints. Instructions fall into a number of broad groups: There are also a few instructions for a number of more specialized tasks such as exception throwing, synchronization, etc. Many instructions have prefixes and/or suffixes referring to the types of operands they operate on. These are as follows: For example, iadd will add two integers, while dadd will add two doubles. The const , load , and store instructions may also take

1440-431: Is written inside classes, and every data item is an object, with the exception of the primitive data types, (i.e. integers, floating-point numbers, boolean values , and characters), which are not objects for performance reasons. Java reuses some popular aspects of C++ (such as the printf method). Unlike C++, Java does not support operator overloading or multiple inheritance for classes, though multiple inheritance

1500-586: The ConcurrentMaps and other multi-core collections, and it was improved further with Java 1.6. Some platforms offer direct hardware support for Java; there are micro controllers that can run Java bytecode in hardware instead of a software Java virtual machine, and some ARM -based processors could have hardware support for executing Java bytecode through their Jazelle option, though support has mostly been dropped in current implementations of ARM. Java uses an automatic garbage collector to manage memory in

1560-500: 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." The bytecode comprises various instruction types, including data manipulation, control transfer, object creation and manipulation, and method invocation, all integral to Java's object-oriented programming model. The JVM

1620-418: The object lifecycle . The programmer determines when objects are created, and the Java runtime is responsible for recovering the memory once objects are no longer in use. Once no references to an object remain, the unreachable memory becomes eligible to be freed automatically by the garbage collector. Something similar to a memory leak may still occur if a programmer's code holds a reference to an object that

1680-503: The stack (for methods) rather than on the heap, as is commonly true for non-primitive data types (but see escape analysis ). This was a conscious decision by Java's designers for performance reasons. Java contains multiple types of garbage collectors. Since Java 9, HotSpot uses the Garbage First Garbage Collector (G1GC) as the default. However, there are also several other garbage collectors that can be used to manage

1740-834: The Java language, as part of J2SE 5.0. Prior to the introduction of generics, each variable declaration had to be of a specific type. For container classes, for example, this is a problem because there is no easy way to create a container that accepts only specific types of objects. Either the container operates on all subtypes of a class or interface, usually Object , or a different container class has to be created for each contained class. Generics allow compile-time type checking without having to create many container classes, each containing almost identical code. In addition to enabling more efficient code, certain runtime exceptions are prevented from occurring, by issuing compile-time errors. If Java prevented all runtime type errors ( ClassCastException s) from occurring, it would be type safe . In 2016,

1800-940: The Java language: As of November 2024 , Java 8, 11, 17, and 21 are supported as long-term support (LTS) versions, with Java 25, releasing in September 2025, as the next scheduled LTS version. Oracle released the last zero-cost public update for the legacy version Java 8 LTS in January 2019 for commercial use, although it will otherwise still support Java 8 with public updates for personal use indefinitely. Other vendors such as Adoptium continue to offer free builds of OpenJDK's long-term support (LTS) versions. These builds may include additional security patches and bug fixes. Major release versions of Java, along with their release dates: Sun has defined and supports four editions of Java targeting different application environments and segmented many of its APIs so that they belong to one of

1860-440: The Java platform must run similarly on any combination of hardware and operating system with adequate run time support. This is achieved by compiling the Java language code to an intermediate representation called Java bytecode , instead of directly to architecture-specific machine code . Java bytecode instructions are analogous to machine code, but they are intended to be executed by a virtual machine (VM) written specifically for

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1920-604: The Java virtual machine, such as: There are several Java virtual machines available today to execute Java bytecode, both free and commercial products. If executing bytecode in a virtual machine is undesirable, a developer can also compile Java source code or bytecode directly to native machine code with tools such as the GNU Compiler for Java (GCJ). Some processors can execute Java bytecode natively. Such processors are termed Java processors . The Java virtual machine provides some support for dynamically typed languages . Most of

1980-630: The ability to run Java applets within web pages, and Java quickly became popular. The Java 1.0 compiler was re-written in Java by Arthur van Hoff to comply strictly with the Java 1.0 language specification. With the advent of Java 2 (released initially as J2SE 1.2 in December 1998 – 1999), new versions had multiple configurations built for different types of platforms. J2EE included technologies and APIs for enterprise applications typically run in server environments, while J2ME featured APIs optimized for mobile applications. The desktop version

2040-579: The community in November 2010. The 0.8 beta was released in December 2010, and 0.8.6 beta was released in mid-2011 with additional typeloaders, making Gosu capable of loading XML schema definition files and XML documents as native Gosu types. The latest version is 1.10, released in January 2016, along with a new IntelliJ IDEA editor plugin. Guidewire continues to support and use Gosu extensively within InsuranceSuite applications. Guidewire has decided to freeze

2100-411: The compiler, is part of the attributes of each method. Each can be independently sized from 0 to 65535 values, where each value is 32 bits. long and double types, which are 64 bits, take up two consecutive local variables (which need not be 64-bit aligned in the local variables array) or one value in the operand stack (but are counted as two units in the depth of the stack). Each bytecode

2160-436: The development of new Gosu programming language constructs at this time. Guidewire continues to evolve InsuranceSuite through RESTful APIs and Integration Frameworks that can be accessed using Java. Gosu language creator and development lead, Scott McKinney, emphasizes pragmatism, found in readability and discoverability , as the overriding principle that guides the language's design. For instance, Gosu's rich static type system

2220-572: The extant JVM instruction set is statically typed - in the sense that method calls have their signatures type-checked at compile time , without a mechanism to defer this decision to run time , or to choose the method dispatch by an alternative approach. JSR 292 ( Supporting Dynamically Typed Languages on the Java Platform ) added a new invokedynamic instruction at the JVM level, to allow method invocation relying on dynamic type checking (instead of

2280-581: The generated servlet creates the response. Swing is a graphical user interface library for the Java SE platform. It is possible to specify a different look and feel through the pluggable look and feel system of Swing. Clones of Windows , GTK+ , and Motif are supplied by Sun. Apple also provides an Aqua look and feel for macOS . Where prior implementations of these looks and feels may have been considered lacking, Swing in Java SE 6 addresses this problem by using more native GUI widget drawing routines of

2340-575: The heap, such as the Z Garbage Collector (ZGC) introduced in Java 11, and Shenandoah GC, introduced in Java 12 but unavailable in Oracle-produced OpenJDK builds. Shenandoah is instead available in third-party builds of OpenJDK, such as Eclipse Temurin . For most applications in Java, G1GC is sufficient. In prior versions of Java, such as Java 8, the Parallel Garbage Collector was used as the default garbage collector. Having solved

2400-658: The host hardware. End-users commonly use a Java Runtime Environment (JRE) installed on their device for standalone Java applications or a web browser for Java applets . Standard libraries provide a generic way to access host-specific features such as graphics, threading , and networking . The use of universal bytecode makes porting simple. However, the overhead of interpreting bytecode into machine instructions made interpreted programs almost always run more slowly than native executables . Just-in-time (JIT) compilers that compile byte-codes to machine code during runtime were introduced from an early stage. Java's Hotspot compiler

2460-547: The implementation of floating-point arithmetic, and a history of security vulnerabilities in the primary Java VM implementation HotSpot . Developers have criticized the complexity and verbosity of the Java Persistence API (JPA), a standard part of Java EE. This has led to increased adoption of higher-level abstractions like Spring Data JPA, which aims to simplify database operations and reduce boilerplate code. The growing popularity of such frameworks suggests limitations in

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2520-530: The introduction of just-in-time compilation in 1997/1998 for Java 1.1 , the addition of language features supporting better code analysis (such as inner classes, the StringBuilder class, optional assertions, etc.), and optimizations in the Java virtual machine, such as HotSpot becoming Sun's default JVM in 2000. With Java 1.5, the performance was improved with the addition of the java.util.concurrent package, including lock-free implementations of

2580-455: The memory management problem does not relieve the programmer of the burden of handling properly other kinds of resources, like network or database connections, file handles, etc., especially in the presence of exceptions. The syntax of Java is largely influenced by C++ and C . Unlike C++, which combines the syntax for structured, generic, and object-oriented programming, Java was built almost exclusively as an object-oriented language. All code

2640-491: The platforms. The platforms are: The classes in the Java APIs are organized into separate groups called packages . Each package contains a set of related interfaces , classes, subpackages and exceptions . Sun also provided an edition called Personal Java that has been superseded by later, standards-based Java ME configuration-profile pairings. One design goal of Java is portability , which means that programs written for

2700-448: The program and can be read by some integrated development environments (IDEs) such as Eclipse to allow developers to access documentation within the IDE. The following is a simple example of a "Hello, World!" program that writes a message to the standard output : Java applets are programs embedded in other applications, mainly in web pages displayed in web browsers. The Java applet API

2760-513: The selling of licenses for specialized products such as the Java Enterprise System. On November 13, 2006, Sun released much of its Java virtual machine (JVM) as free and open-source software (FOSS), under the terms of the GPL-2.0-only license. On May 8, 2007, Sun finished the process, making all of its JVM's core code available under free software /open-source distribution terms, aside from

2820-464: The specifications for Java bytecode are now available, other parties have supplied compilers that produce Java bytecode. Examples of other compilers include: Some projects provide Java assemblers to enable writing Java bytecode by hand. Assembly code may be also generated by machine, for example by a compiler targeting a Java virtual machine . Notable Java assemblers include: Others have developed compilers, for different programming languages, to target

2880-539: The specifications of the Java Community Process , Sun had relicensed most of its Java technologies under the GPL-2.0-only license. Oracle offers its own HotSpot Java Virtual Machine, however the official reference implementation is the OpenJDK JVM which is free open-source software and used by most developers and is the default JVM for almost all Linux distributions. As of September 2024 , Java 23

2940-436: The stack. There is also an aconst_null , which pushes a null reference. The n for the load and store instructions specifies the index in the local variable array to load from or store to. The aload_0 instruction pushes the object in local variable 0 onto the stack (this is usually the this object). istore_1 stores the integer on the top of the stack into local variable 1. For local variables beyond 3

3000-464: The standard JPA implementation's ease-of-use for modern Java development. The Java Class Library is the standard library , developed to support application development in Java. It is controlled by Oracle in cooperation with others through the Java Community Process program. Companies or individuals participating in this process can influence the design and development of the APIs. This process has been

3060-452: The suffix is dropped and operands must be used. Consider the following Java code: A Java compiler might translate the Java code above into bytecode as follows, assuming the above was put in a method: The most common language targeting Java virtual machine by producing Java bytecode is Java. Originally only one compiler existed, the javac compiler from Sun Microsystems , which compiles Java source code to Java bytecode; but because all

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3120-464: The type system as well as structural typing similar to the Go programming language. Gosu supports several file types: In addition to standard class types Gosu supports enums, interfaces, structures, and annotations. Program files facilitate Gosu as a scripting language. For example, Gosu's Hello, World! is a simple one-line program: Gosu classes are also executable a la Java: A unique feature of Gosu

3180-409: The type system of Java was proven unsound in that it is possible to use generics to construct classes and methods that allow assignment of an instance one class to a variable of another unrelated class. Such code is accepted by the compiler, but fails at run time with a class cast exception. Criticisms directed at Java include the implementation of generics, speed, the handling of unsigned numbers,

3240-434: The underlying computer architecture . The syntax of Java is similar to C and C++ , but has fewer low-level facilities than either of them. The Java runtime provides dynamic capabilities (such as reflection and runtime code modification) that are typically not available in traditional compiled languages. Java gained popularity shortly after its release, and has been a very popular programming language since then. Java

3300-571: The underlying platforms. JavaFX is a software platform for creating and delivering desktop applications , as well as rich web applications that can run across a wide variety of devices. JavaFX is intended to replace Swing as the standard GUI library for Java SE , but since JDK 11 JavaFX has not been in the core JDK and instead in a separate module. JavaFX has support for desktop computers and web browsers on Microsoft Windows , Linux , and macOS . JavaFX does not have support for native OS look and feels. In 2004, generics were added to

3360-417: The web service methods for the actual business logic. JavaServer Pages ( JSP ) are server-side Java EE components that generate responses, typically HTML pages, to HTTP requests from clients . JSPs embed Java code in an HTML page by using the special delimiters <% and %> . A JSP is compiled to a Java servlet , a Java application in its own right, the first time it is accessed. After that,

3420-440: Was deprecated with the release of Java 9 in 2017. Java servlet technology provides Web developers with a simple, consistent mechanism for extending the functionality of a Web server and for accessing existing business systems. Servlets are server-side Java EE components that generate responses to requests from clients . Most of the time, this means generating HTML pages in response to HTTP requests, although there are

3480-665: Was initially called Oak after an oak tree that stood outside Gosling's office. Later the project went by the name Green and was finally renamed Java , from Java coffee , a type of coffee from Indonesia . Gosling designed Java with a C / C++ -style syntax that system and application programmers would find familiar. Sun Microsystems released the first public implementation as Java 1.0 in 1996. It promised write once, run anywhere (WORA) functionality, providing no-cost run-times on popular platforms . Fairly secure and featuring configurable security, it allowed network- and file-access restrictions. Major web browsers soon incorporated

3540-675: Was renamed J2SE. In 2006, for marketing purposes, Sun renamed new J2 versions as Java EE , Java ME , and Java SE , respectively. In 1997, Sun Microsystems approached the ISO/IEC JTC 1 standards body and later the Ecma International to formalize Java, but it soon withdrew from the process. Java remains a de facto standard , controlled through the Java Community Process . At one time, Sun made most of its Java implementations available without charge, despite their proprietary software status. Sun generated revenue from Java through

3600-622: Was the third most popular programming language in 2022 according to GitHub . Although still widely popular, there has been a gradual decline in use of Java in recent years with other languages using JVM gaining popularity. Java was originally developed by James Gosling at Sun Microsystems . It was released in May 1995 as a core component of Sun's Java platform . The original and reference implementation Java compilers , virtual machines, and class libraries were originally released by Sun under proprietary licenses . As of May 2007, in compliance with

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