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64-460: CLDC is designed for devices that have limited processing power, memory, and graphical capability. Devices typically have the following features: Compared to the Java SE environment, several APIs are absent entirely, and some APIs are altered such that code requires explicit changes to support CLDC. In particular, certain changes are not just the absence of classes or interfaces, but actually change

128-476: A Proxy class that supports dynamic creation of proxy classes that implement specified interfaces. The implementation of a Proxy class is provided by a supplied object that implements the InvocationHandler interface. The InvocationHandler 's invoke(Object, Method, Object[]) method is called for each method invoked on the proxy object—the first parameter is the proxy object,

192-574: A basic 2D gaming API. Applications written to use this profile are called MIDlets . Many cell phones come with a MIDP implementation, and it is a popular platform for downloadable cell phone games. The Information Module Profile is specified in JSR 195 and is designed for vending machines , network cards, routers, telephone boxes and other systems with either simple or no display and some form of limited two way network access. Only APIs for application creation, storage, and network access are defined. These are

256-465: A bean editing tool, in which beans can be combined, customized, and manipulated. One type of bean editor is a GUI designer in an integrated development environment . The java.awt , or Abstract Window Toolkit, provides access to a basic set of GUI widgets based on the underlying native platform's widget set, the core of the GUI event subsystem, and the interface between the native windowing system and

320-607: A build of OpenJDK for users of the Windows Azure cloud. Zulu is available as a free download from the community site Zulu.org . It is also possible to get Zulu on Amazon Web Services via Canonical's Juju Charm Store, the Docker Hub, and Azul Systems repositories. Azul contributes bug fixes and enhancements back to the OpenJDK project and has several project committers on staff. Red Hat resigned leadership of OpenJDK 6 at

384-410: A byte-offset within the file for the next read or write operation. The file pointer is moved implicitly by reading or writing and explicitly by calling the seek(long) or skipBytes(int) methods. The current position of the file pointer is returned by the getFilePointer() method. The File class represents a file or directory path in a file system . File objects support

448-436: A certified collection of Java APIs for the development of software for small, resource-constrained devices such as cell phones , PDAs and set-top boxes . The Java Runtime Environment (JRE) and Java Development Kit (JDK) are the actual files downloaded and installed on a computer to run or develop Java programs, respectively. The Java package java.lang contains fundamental classes and interfaces closely tied to

512-617: A feature release every six months according to a strict, time-based model. Due to Oracle no longer releasing updates for long-term support (LTS) releases under a permissive license, other organizations have begun to publish their own builds, both in regular and long-term support terms. Many Linux distributions offer their own builds through their package manager , including Microsoft Windows . In order to bundle OpenJDK in Fedora and other free Linux distributions, OpenJDK needed to be buildable using only free software components. Due to

576-417: A few miscellaneous classes to support interactions with the host file system . The stream classes follow the decorator pattern by extending the base subclass to add features to the stream classes. Subclasses of the base stream classes are typically named for one of the following attributes: The stream subclasses are named using the naming pattern XxxStreamType where Xxx is the name describing

640-478: A file, but can also be a console or network socket . FileDescriptor objects are used to create File streams. They are obtained from File streams and java.net sockets and datagram sockets. In J2SE 1.4, the package java.nio (NIO or Non-blocking I/O) was added to support memory-mapped I/O , facilitating I/O operations closer to the underlying hardware with sometimes dramatically better performance. The java.nio package provides support for

704-636: A number of buffer types. The subpackage java.nio.charset provides support for different character encodings for character data. The subpackage java.nio.channels provides support for channels, which represent connections to entities that are capable of performing I/O operations, such as files and sockets. The java.nio.channels package also provides support for fine-grained locking of files. The java.math package supports multiprecision arithmetic (including modular arithmetic operations) and provides multiprecision prime number generators used for cryptographic key generation. The main classes of

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768-826: A set of APIs for the development of applications for set-top boxes and similar devices. The profile consists of subsets from the CDC Personal Basis Profile including support for AWT , Xlet , file access, and network APIs, as well as several media-related interfaces from OCAP. The whole profile encompassed 31 Java packages and approximately 1500 APIs. The PDA Optional Packages are specified in JSR-75 and are designed for PDAs such as Palm or Windows CE devices. The specification defines two independent packages that represent important features found on many PDAs and other mobile devices. These packages are: Java SE Java Platform, Standard Edition ( Java SE )

832-631: A subset of the javax.microedition.io, rms and midlet packages in MIDP. Siemens Mobile and Nokia put forward this specification to the JCP. The DoJa profile was designed for the i-mode mobile phone by NTT DoCoMo . The Digital Set Top Box profile, specified in JSR 242, is designed for the cable market. Also referred to as OnRamp , this profile is based on a subset of the OpenCable Application Platform ( OCAP ), which defines

896-532: 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 the 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

960-561: Is a collection of routines that build on java.awt to provide a platform independent widget toolkit . javax.swing uses the 2D drawing routines to render the user interface components instead of relying on the underlying native operating system GUI support. This package contains the largest number of classes (133 in all) in JDK 6. This package, along with java.awt also contains the largest number of enums (7 in all) in JDK 6. It supports pluggable looks and feels (PLAFs) so that widgets in

1024-485: Is a constituent of the Java API that lets Java code examine and "reflect" on Java components at runtime and use the reflected members. Classes in the java.lang.reflect package, along with java.lang.Class and java.lang.Package accommodate applications such as debuggers , interpreters , object inspectors, class browsers , and services such as object serialization and JavaBeans that need access to either

1088-615: Is a set of APIs that support devices with different capabilities and resources within the CLDC framework to provide a complete Java application environment. There are specific profiles for devices ranging from vending machines to set-top boxes, with the mobile phone profile MIDP being the most prevalent. The Mobile Information Device Profile is a profile designed for cell phones. There are two versions of MIDP available, specified in JSR 37 (MIDP 1.0) and JSR 118 (MIDP 2.0). Both versions provide an LCD oriented GUI API, with MIDP 2.0 including

1152-468: Is accomplished through stream filters . The filter classes all accept another compatible stream object as a parameter to the constructor and decorate the enclosed stream with additional features. Filters are created by extending one of the base filter classes FilterInputStream , FilterOutputStream , FilterReader , or FilterWriter . The Reader and Writer classes are really just byte streams with additional processing performed on

1216-461: Is known as a "strong reference". The java.lang.ref package defines three other types of references—soft, weak , and phantom references. Each type of reference is designed for a specific use. Each of these reference types extends the Reference class, which provides the get() method to return a strong reference to the referent object (or null if the reference has been cleared or if

1280-517: Is the Collections API , an organized data structure hierarchy influenced heavily by the design patterns considerations. Created to support Java applet creation, the java.applet package lets applications be downloaded over a network and run within a guarded sandbox. Security restrictions are easily imposed on the sandbox. A developer, for example, may apply a digital signature to an applet, thereby labeling it as safe. Doing so allows

1344-534: Is the official reference implementation of Java SE since version 7, and is the most popular distribution of the JDK. Sun announced in JavaOne 2006 that Java would become open-source software, and on October 25, 2006, at the Oracle OpenWorld conference, Jonathan Schwartz said that the company intended to announce the open-sourcing of the core Java Platform within 30 to 60 days. Sun released

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1408-693: The Fedora 9 and Ubuntu 8.04 distributions included IcedTea 6, based completely on free and open source code. Fedora 9 was the first version to be shipped with IcedTea6, based on the OpenJDK6 sources from Sun rather than OpenJDK7. It was also the first to use OpenJDK for the package name (via the OpenJDK trademark agreement ) instead of IcedTea. Ubuntu also first packaged IcedTea7 before later moving to IcedTea6. Packages for IcedTea6 were also created for Debian and included in Lenny . On July 12, 2008, Debian accepted OpenJDK-6 in unstable, and it later

1472-632: The Itanium platform was released. The number of external contributions to OpenJDK is growing since project inception. OpenJDK 11, released in September 2018, received 20% of external fixes and brought 17 new JEPs (features), out of which 3 were contributed by the community. Namely, JEP 315: "Improve Aarch64 Intrinsics" (contributed by BellSoft ), JEP 318: "Epsilon: A No-Op Garbage Collector" (by Red Hat) and JEP 331: "Low-Overhead Heap Profiling" (contributed by Google). On October 11, 2010, IBM , by far

1536-716: The Java Language Specification and the Java Virtual Machine Specification . OpenJDK is the official reference implementation since version 7. 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"

1600-591: The Java Platform, Standard Edition (Java SE). It is the result of an effort Sun Microsystems began in 2006, four years before the company was acquired by Oracle Corporation . The implementation is licensed under the GNU General Public License 2 with a linking exception , preventing components that linked to the Java Class Library becoming subject to the terms of the GPL license. OpenJDK

1664-554: The encumbered components in the class library and implicit assumptions within the build system that the JDK being used to build OpenJDK was a Sun JDK, this was not possible. To achieve openness, Red Hat started the IcedTea project in June 2007. It began life as an OpenJDK/ GNU Classpath hybrid that could be used to bootstrap OpenJDK, replacing the encumbrances with code from GNU Classpath. On November 5, 2007, Red Hat signed both

1728-549: The "Java trap", the vendor lock-in that he argues applied to Java and programs written in Java. Following their promise to release a Java Development Kit (JDK) based almost completely on free and open-source code in the first half of 2007, Sun released the complete source code of the Java Class Library under the GPL on May 8, 2007, except for some limited parts that had been licensed to Sun by third parties and Sun

1792-589: The BSD one) led by Landon Fuller have expressed interest in joining OpenJDK via the Porters Group. As of January 2008, both are part of the mailing list discussions. Another project pending formalization on the Porters Group is the Haiku Java Team led by Bryan Varner. In December 2007, Sun moved the revision control of OpenJDK from TeamWare to Mercurial (and later to Git and GitHub ), as part of

1856-576: The GUI can imitate those from the underlying native system. Design patterns permeate the system, especially a modification of the model–view–controller pattern, which loosens the coupling between function and appearance. One inconsistency is that (as of J2SE 1.3) fonts are drawn by the underlying native system, and not by Java, limiting text portability. Workarounds, such as using bitmap fonts, do exist. In general, "layouts" are used and keep elements within an aesthetically consistent GUI across platforms. The javax.swing.text.html.parser package provides

1920-532: The JVM has about the program. There are basic techniques involved in reflection: Discovery typically starts with an object and calling the Object.getClass() method to get the object's Class . The Class object has several methods for discovering the contents of the class, for example: The Class object can be obtained either through discovery, by using the class literal (e.g. MyClass.class ) or by using

1984-573: The Java HotSpot virtual machine and compiler as free software under the GNU General Public License on November 13, 2006, with a promise that the rest of the JDK (which includes the Java Runtime Environment ) would be placed under the GPL by March 2007, "except for a few components that Sun does not have the right to publish in source form under the GPL". According to free-software advocate Richard Stallman , this would end

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2048-625: The Java application. It also provides several basic layout managers , a datatransfer package for use with the Clipboard and Drag and Drop , the interface to input devices such as mice and keyboards , as well as access to the system tray on supporting systems. This package, along with javax.swing contains the largest number of enums (7 in all) in JDK 6. The java.rmi package provides Java remote method invocation to support remote procedure calls between two java applications running in different JVMs . Support for security, including

2112-491: The OpenJDK project for Mac OS X. Apple will contribute most of the key components, tools and technology required for a Java SE 7 implementation on Mac OS X, including a 32-bit and 64-bit HotSpot-based Java virtual machine, class libraries, a networking stack and the foundation for a new graphical client. On January 11, 2011, the Mac OS X Port Project was created on OpenJDK, and Apple made the first public contribution of code to

2176-633: The Sun Contributor Agreement and the OpenJDK Community TCK License. One of the first benefits of this agreement is tighter alignment with the IcedTea project, which brings together Fedora , the Linux distribution, and JBoss , the application server, technologies in a Linux environment. IcedTea provided free software alternatives for the few remaining proprietary sections in the OpenJDK project. In May 2008,

2240-583: The appearance of OpenJDK 6 in May 2008, less than 1% (the SNMP implementation, which is not part of the Java specification) remained, making it possible to build OpenJDK without any binary plugs. The binary plug requirement was later dropped from OpenJDK 7 as part of b53 in April 2009. This was made possible, over the course of the first year, by the work of Sun Microsystems and the OpenJDK community. Each encumbrance

2304-568: The application and the Java Virtual Machine (JVM) garbage collector . It is an important package, central enough to the language for the language designers to give it a name that starts with "java.lang", but it is somewhat special-purpose and not used by a lot of developers. This package was added in J2SE 1.2. Java has an expressive system of references and allows for special behavior for garbage collection. A normal reference in Java

2368-556: The beginning of 2017 and this was then taken up by Azul Systems. Since April 2016 there are unsupported community builds of OpenJDK for Microsoft Windows on GitHub in the project ojdkbuild which are released in pace with updates for Oracle JDK. From build 8u151 on, the MSI-installer offers an optional component for using Java Web Start based on the IcedTea-Web project. In 2020, a port of OpenJDK 8 to OpenVMS on

2432-641: The biggest participant in the Apache Harmony project, decided to join Oracle on the OpenJDK project, effectively shifting its efforts from Harmony to OpenJDK. Bob Sutor, IBM's head of Linux and open source, blogged that "IBM will be shifting its development effort from the Apache Project Harmony to OpenJDK". On November 12, 2010, Apple Inc. (just three weeks after deprecating its own Java runtime port ) and Oracle Corporation announced

2496-428: The character encoding to use. If no encoding is specified, the program uses the default encoding for the platform. The following table shows the other processes and filters that the java.io package directly supports. All these classes extend the corresponding Filter class. The RandomAccessFile class supports random access reading and writing of files. The class uses a file pointer that represents

2560-628: The company access to the test suite that determines whether a project based on OpenJDK complies with the Java SE 6 specification). Also in November 2007, the Porters Group was created on OpenJDK to aid in efforts to port OpenJDK to different processor architectures and operating systems . The BSD porting project led by Kurt Miller and Greg Lewis and the Mac OS X porting project (based on

2624-487: The compatibility tests in the Java SE 6 TCK . Since August 2008, OpenJDK 7 is usable on macOS and other BSD variants. On Android Nougat , OpenJDK replaced the now-discontinued Apache Harmony as the Java libraries in the source code of the mobile operating system . Google was in a legal dispute with Oracle over claims of copyright and patent infringement through its use of re-implementations of copyrighted Java APIs via Harmony. While also stating that this change

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2688-400: The creation, deletion and renaming of files and directories and the manipulation of file attributes such as read-only and last modified timestamp . File objects that represent directories can be used to get a list of all the contained files and directories. The FileDescriptor class is a file descriptor that represents a source or sink (destination) of bytes. Typically this is

2752-590: The data stream to convert the bytes to characters. They use the default character encoding for the platform, which as of J2SE 5.0 is represented by the Charset returned by the java.nio.charset.Charset.defaultCharset() static method. The InputStreamReader class converts an InputStream to a Reader and the OutputStreamWriter class converts an OutputStream to a Writer . Both these classes have constructors that support specifying

2816-399: The error tolerant HTML parser that is used for writing various web browsers and web bots. The javax.xml.bind.annotation package contained the largest number of Annotation Types (30 in all) in JDK 6. It defines annotations for customizing Java program elements to XML Schema mapping. OpenJDK OpenJDK ( Open Java Development Kit ) is a free and open-source implementation of

2880-621: The feature and StreamType is one of InputStream , OutputStream , Reader , or Writer . The following table shows the sources/destinations supported directly by the java.io package: Other standard library packages provide stream implementations for other destinations, such as the InputStream returned by the java.net.Socket.getInputStream() method or the Java EE javax.servlet.ServletOutputStream class. Data type handling and processing or filtering of stream data

2944-619: The language and runtime system. This includes the root classes that form the class hierarchy , types tied to the language definition, basic exceptions , math functions, threading , security functions, as well as some information on the underlying native system. This package contains 22 of 32 Error classes provided in JDK 6. The main classes and interfaces in java.lang are: Classes in java.lang are automatically imported into every source file . The java.lang.ref package provides more flexible types of references than are otherwise available, permitting limited interaction between

3008-535: The message digest algorithm, is included in the java.security package. An implementation of the JDBC API (used to access SQL databases ) is grouped into the java.sql package. The javax.rmi package provided support for the remote communication between applications, using the RMI over IIOP protocol. This protocol combines RMI and CORBA features. Java SE Core Technologies - CORBA / RMI-IIOP Swing

3072-525: The name of the class (e.g. Class.forName("mypackage.MyClass") ). With a Class object, member Method , Constructor , or Field objects can be obtained using the symbolic name of the member. For example: Method , Constructor , and Field objects can be used to dynamically access the represented member of the class. For example: The java.lang.reflect package also provides an Array class that contains static methods for creating and manipulating array objects, and since J2SE 1.3,

3136-450: The package are primarily stream-oriented ; however, a class for random access files is also provided. The central classes in the package are InputStream and OutputStream , which are abstract base classes for reading from and writing to byte streams , respectively. The related classes Reader and Writer are abstract base classes for reading from and writing to character streams, respectively. The package also has

3200-410: The package are: The java.net package provides special IO routines for networks, allowing HTTP requests, as well as other common transactions. The java.text package implements parsing routines for strings and supports various human-readable languages and locale-specific parsing. Data structures that aggregate objects are the focus of the java.util package. Included in the package

3264-522: The process of releasing it to open-source communities. OpenJDK has comparatively strict procedures of accepting code contributions: every proposed contribution must be reviewed by another OpenJDK committer and the contributor must have signed the Sun/Oracle Contributor Agreement (SCA/OCA). Preferably, there should also be a jtreg test demonstrating the bug has been fixed. Initially, the external patch submission process

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3328-878: The project. The initial Apple contribution built on the OpenJDK BSD port. In July 2011, SAP AG announced that SAP officially joined the OpenJDK project. 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 Corporation have done so. The only currently available free plugin and Web Start implementations as of 2016 are those provided by IcedTea . OpenJDK 9+ supports AOT compilation ( jaotc ) using GraalVM (JEP 295). The experimental -XX:+EnableJVMCIProduct flag enables

3392-419: The public members of a target object (based on its runtime class) or the members declared by a given class. This package was added in JDK 1.1. Reflection is used to instantiate classes and invoke methods using their names, a concept that allows for dynamic programming. Classes, interfaces, methods, fields , and constructors can all be discovered and used at runtime. Reflection is supported by metadata that

3456-472: The reference type is phantom), and the clear() method to clear the reference. The java.lang.ref also defines the class ReferenceQueue , which can be used in each of the applications discussed above to keep track of objects that have changed reference type. When a Reference is created it is optionally registered with a reference queue. The application polls the reference queue to get references that have changed reachability state. Reflection

3520-481: The second parameter is the Method object representing the method from the interface implemented by the proxy, and the third parameter is the array of parameters passed to the interface method. The invoke() method returns an Object result that contains the result returned to the code that called the proxy interface method. The java.io package contains classes that support input and output . The classes in

3584-542: The signatures of existing classes in the base class library. An example of this is the absence of the Serializable interface, which does not appear in the base class library due to restrictions on reflection usage. All java.lang.* classes which normally implement Serializable do not, therefore, implement this tagging interface . Other examples of limitations depend on the version being used, as some features were re-introduced with version 1.1 of CLDC. A profile

3648-606: The use of Graal JIT (JEP 317). OpenJDK was initially based only on the JDK 7 version of the Java platform. Since JDK 10, the effort to produce an open-source reference implementation of the Java SE Platform was moved over to the JDK Project. Unlike past JDK Release Projects, which produced just one feature release and then terminated, this long-running project will produce all future JDK feature releases and will ship

3712-625: The user to grant the applet permission to perform restricted operations (such as accessing the local hard drive), and removes some or all the sandbox restrictions. Digital certificates are issued by certificate authorities . Included in the java.beans package are various classes for developing and manipulating beans, reusable components defined by the JavaBeans architecture . The architecture provides mechanisms for manipulating properties of components and firing events when those properties change. The APIs in java.beans are intended for use by

3776-642: Was either released as free and open-source software or replaced with an alternative. Beginning in December 2010, all the so-called binary plugs were replaced by open-source replacements, making the whole JDK open sourced and the binary plugs not necessary anymore. On November 5, 2007, Red Hat announced an agreement with Sun, signing Sun's broad contributor agreement (which covers participation in all Sun-led free and open-source software projects by all Red Hat engineers) and Sun's OpenJDK Community Technology Compatibility Kit (TCK) License Agreement (which gives

3840-517: Was included in stable . OpenJDK is also available on openSUSE , Red Hat Enterprise Linux and RHEL derivatives such as CentOS . In June 2008, Red Hat announced that the packaged binaries for OpenJDK on Fedora 9 , built using IcedTea 6, had passed the Technology Compatibility Kit tests and could claim to be a fully compatible Java 6 implementation. In July 2009, an IcedTea 6 binary build for Ubuntu 9.04 passed all of

3904-508: Was originally intended to emphasize the major changes introduced in version 1.2, but was removed in version 1.6. The naming convention has been changed several times over the Java version history . Starting with J2SE 1.4 (Merlin), Java SE has been developed under the Java Community Process , which produces descriptions of proposed and final specifications for the Java platform called Java Specification Requests (JSR) . JSR 59

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3968-506: Was slow and, until September 2008, commits to the codebase were only made by Sun engineers. The process has improved and, as of 2010 , simple patches and backports from OpenJDK 7 to OpenJDK 6 can take place within hours rather than days. In 2011, an unofficial port of OpenJDK 6.0 to OS/2 was first released. This port is included in the OS/2 derivative ArcaOS . On 25 September 2013, Microsoft and Azul Systems collaborated to create Zulu,

4032-439: Was the umbrella specification for J2SE 1.4 and JSR 176 specified J2SE 5.0 (Tiger). Java SE 6 (Mustang) was released under JSR 270. Java Platform, Enterprise Edition (Java EE) is a related specification that includes all the classes in Java SE, plus a number that are more useful to programs that run on servers as opposed to workstations . Java Platform, Micro Edition (Java ME) is a related specification intended to provide

4096-413: Was unable to re-license under the GPL. Included in the list of encumbered parts were several major components of the Java graphical user interface (GUI). Sun stated that it planned to replace the remaining proprietary components with alternative implementations and to make the class library completely free. When initially released in May 2007, 4% of the OpenJDK class library remained proprietary. By

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