Comparison of the Java and .NET platforms

Standardization

The two platforms, their programming libraries, their binary formats, and their runtime environments have largely been governed by very different means.

The .NET platform as a whole has not been standardized. International standards organizations Ecma International

Ecma International

Ecma International is an international, private non-profit standards organization for information and communication systems. It acquired its name in 1994, when the European Computer Manufacturers Association changed its name to reflect the organization's global reach and activities...

and ISO/IEC

International Electrotechnical Commission

The International Electrotechnical Commission is a non-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as "electrotechnology"...

define the standard for the .NET executable environment (known as the Common Language Infrastructure, or CLI), and .NET executable format (known as Common Intermediate Language, or CIL), but excluding most of the foundation classes (the Base Class Library, or BCL). This formal committee-based standardization process is in keeping with the way very popular languages like COBOL

COBOL

COBOL is one of the oldest programming languages. Its name is an acronym for COmmon Business-Oriented Language, defining its primary domain in business, finance, and administrative systems for companies and governments....

, Fortran

Fortran

Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...

and C have been standardized in the past. The standards do not include many new libraries that Microsoft has implemented on top of the standard framework, such as those for accessing databases, or building GUI and Web applications, such as Windows Forms

Windows Forms

Windows Forms is the name given to the graphical application programming interface included as a part of Microsoft .NET Framework, providing access to native Microsoft Windows interface elements by wrapping the extant Windows API in managed code...

, ASP.NET

ASP.NET

ASP.NET is a Web application framework developed and marketed by Microsoft to allow programmers to build dynamic Web sites, Web applications and Web services. It was first released in January 2002 with version 1.0 of the .NET Framework, and is the successor to Microsoft's Active Server Pages ...

and ADO.NET

ADO.NET

ADO.NET is a set of computer software components that programmers can use to access data and data services. It is a part of the base class library that is included with the Microsoft .NET Framework. It is commonly used by programmers to access and modify data stored in relational database systems,...

.
To date, no part of Java has been standardized by Ecma International

Ecma International

, ISO/IEC

International Electrotechnical Commission

, ANSI

Ansi

Ansi is a village in Kaarma Parish, Saare County, on the island of Saaremaa, Estonia....

, or any other third-party standards organization. While 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...

has unlimited and exclusive legal rights to modify and license its Java trademarks, Sun voluntarily participates in a process called the Java Community Process

Java Community Process

The Java Community Process or JCP, established in 1998, is a formalized process that allows interested parties to get involved in the definition of future versions and features of the Java platform....

(JCP) that allows interested parties to propose changes to any of Sun's Java technologies (from language and tools to API) via forums, consultation exercises and expert groups. The JCP requires a membership fee for commercial contributors, while non-commercial contributors and individuals can join for free.

Within the rules of the JCP anyone can bring forward a proposal for a new Platform Edition Specifications or suggest changes to the Java language. All proposals are reviewed and voted on by interested JCP members at various stages throughout their lifecycle, however when it comes to including changes into the standard reference implementations (Java SE, Java EE and Java ME) modifications may be subject to rejection by Sun, who retain ultimate power of veto.

Java standards are maintained by a suite of test applications which examine every aspect of a given Java implementation against a rigorous specification. Only if an implementation passes the tens of thousands of individual tests can it use the trademarked name "Java", and associated logos and brands.

Java

The primary implementation of the Java platform is available as an Open Source implementation called OpenJDK.

While "Java" is an Oracle trademark, and only Oracle can license the name "Java", numerous free software projects exist that are compatible with Oracle Java. Most notably, 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...

and GCJ provide a free software class library and a compiler that are partially compatible with the current version of OracleJava. Sun announced on November 13, 2006 that all Java source code, excluding closed-source code for which they do not retain rights, will be released under a modified version of the GPL

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....

, and released two fundamental parts of the JRE and JDK: HotSpot

HotSpot

HotSpot is a Java virtual machine for desktops and servers, maintained and distributed by Oracle Corporation. It features techniques such as just-in-time compilation and adaptive optimization designed to improve performance.-History:...

and the javac

Javac

javac is the primary Java compiler, included in the Java Development Kit from Oracle Corporation.The compiler accepts source code conforming to the Java language specification and produces bytecode conforming to the Java Virtual Machine Specification .javac is itself written in Java...

compiler under the GPL

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....

.

Following their promise, Sun released the complete source code

Source code

In computer science, source code is text written using the format and syntax of the programming language that it is being written in. Such a language is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source...

of the Class library under GPL on May 8, 2007, except some limited parts that were licensed by Sun from 3rd parties who did not want their code to be released under an open-source license (see also Free Java implementations). Sun's goal is to replace the parts that remain closed with alternative implementations and make the class library completely open.

In June 2008, Red Hat

Red Hat

Red Hat, Inc. is an S&P 500 company in the free and open source software sector, and a major Linux distribution vendor. Founded in 1993, Red Hat has its corporate headquarters in Raleigh, North Carolina with satellite offices worldwide....

announced that the IcedTea

IcedTea

IcedTea is a build and integration project for OpenJDK launched by Red Hat in June 2007. The initial goal was to make the Java OpenJDK software which Sun Microsystems released as free software in 2007 usable without requiring any other software that is not free software and hence make it possible...

project has passed the rigorous Java TCK

Technology Compatibility Kit

A Technology Compatibility Kit is a suite of tests that at least nominally checks a particular alleged implementation of a Java Specification Request for compliance...

, indicating a fully functional open-source implementation of the Java platform.

.NET

Microsoft's .NET CLI executable environment, and some of the corresponding class library, have been standardized and can be freely implemented without a license. A few standards-compliant free software environments have been implemented, such as the Mono Project and DotGNU

DotGNU

DotGNU is a part of the GNU Project that aims to provide a free software replacement for Microsoft's .NET Framework by Free Software Foundation...

. The Mono Project has also implemented many of Microsoft's non-standard libraries by examining Microsoft materials, similar to GNU Classpath and Java.

Microsoft is currently distributing a shared source

Shared Source Common Language Infrastructure

The Shared Source Common Language Infrastructure , previously codenamed Rotor, is Microsoft's shared source implementation of the CLI, the core of .NET. Although the SSCLI is not suitable for commercial use due to its license, it does make it possible for programmers to examine the implementation...

version of its .NET runtime environment for academic use, however it is only supported on Windows 7 and has not been updated after .NET 4.0.

The Mono project aims to avoid infringing on any patents or copyrights, and to the extent that they are successful, the project can be safely distributed and used under the GPL

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....

. On November 2, 2006, Microsoft and Novell announced a joint agreement whereby Microsoft promised not to sue Novell or its customers for patent infringement. According to a statement on the blog of Mono project leader Miguel de Icaza

Miguel de Icaza

Miguel de Icaza is a Mexican free software programmer, best known for starting the GNOME and Mono projects.-Early years:Miguel de Icaza was born in Mexico City and studied at the Universidad Nacional Autonoma de México but never received a degree. He came from a family of scientists in which his...

, this agreement only extends to Mono for Novell developers and users. Because of the possible threat of Microsoft patents, the FSF

Free Software Foundation

The Free Software Foundation is a non-profit corporation founded by Richard Stallman on 4 October 1985 to support the free software movement, a copyleft-based movement which aims to promote the universal freedom to create, distribute and modify computer software...

recommends that people avoid creating software that depends on Mono or C#.

The Microsoft/Novell agreement was criticized by some in the open source

Open source

The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

community because it violates the principles of giving equal rights to all users of a particular program (see Agreement with Microsoft and Mono and Microsoft's patents).

In response to the Microsoft/Novell agreement the Free Software Foundation

Free Software Foundation

revised its 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....

to close the loophole used by Microsoft and Novell to bypass the GPL's very restrictive provisions on patent deals. The FSF also stated that by selling coupons for Novell's Linux software, the mechanism by which Microsoft circumvented the GNU license, it considers Microsoft to be a Linux vendor, and thereby subject to the full terms and conditions laid out in the GPL.

Community

Oracle retains exclusive and unlimited legal rights to its Java intellectual properties

Intellectual property

Intellectual property is a term referring to a number of distinct types of creations of the mind for which a set of exclusive rights are recognized—and the corresponding fields of law...

, and the Java community is subject to those rights.

While Microsoft

Microsoft

Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

has developed C# and .NET without a formal community contribution system, the language and some parts of the executable format and runtime have been standardized and freely distributed through Ecma and ISO in an open and vendor-neutral process, rather than a process that retains veto and copy rights for Microsoft. However, the standards do not include many new libraries that Microsoft has implemented on top of the standard framework (see Standardization). Numerous C# and CLI community software projects, help and documentation sites, and discussion forums are under active development and maintenance.

Microsoft is distributing a shared source

Shared source

Shared source is an umbrella term covering some of Microsoft's legal mechanisms for software source code distribution. Microsoft's Shared Source Initiative, launched in May 2001, includes a spectrum of technologies and licenses...

release (version 1.0) of the .NET virtual machine that can be compiled and used on Windows, FreeBSD, Mac OS X, and other platforms. An updated version (2.0) is currently available, but the only officially supported platform is Windows. A community port to Linux of the 1.0 shared source .NET virtual machine is also available. In March 2003, O'Reilly Media published a book about Microsoft's shared source .NET runtime.

Desktop applications

Although Java's AWT

Abstract Window Toolkit

The Abstract Window Toolkit is Java's original platform-independent windowing, graphics, and user-interface widget toolkit. The AWT is now part of the Java Foundation Classes — the standard API for providing a graphical user interface for a Java program.AWT is also the GUI toolkit for a...

(Abstract Windowing Toolkit) and Swing

Swing (Java)

Swing is the primary Java GUI widget toolkit. It is part of Oracle's Java Foundation Classes — an API for providing a graphical user interface for Java programs....

libraries are not shy of features, Java has struggled to establish a foothold in the desktop market. 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...

has also been slow, in the eyes of some, to promote Java to developers and end users alike in a way which makes it an appealing choice for desktop software. Even technologies such as Java Web Start

Java Web Start

In computing, Java Web Start is a framework developed by Sun Microsystems that allows users to start application software for the Java Platform directly from the Internet using a web browser....

, which have few parallels within rival languages and platforms, have barely been promoted.

The release of Java version 6.0 on December 11, 2006, saw a renewed focus on the desktop market with an extensive set of new tools for closer integration with the desktop. At the 2007 JavaOne

JavaOne

JavaOne is an annual conference inaugurated in 1996 by Sun Microsystems to discuss Java technologies, primarily among Java developers. JavaOne is held in San Francisco, California typically running from Monday to Thursday. Technical sessions on a variety of topics are held during the day. In the...

conference Sun made further desktop related announcements, including a new language aimed at taking on Adobe Flash

Adobe Flash

Adobe Flash is a multimedia platform used to add animation, video, and interactivity to web pages. Flash is frequently used for advertisements, games and flash animations for broadcast...

(JavaFX

JavaFX

JavaFX is a software platform for creating and delivering rich Internet applications that can run across a wide variety of connected devices....

), a new lightweight way of downloading the JRE which sees the initial footprint reduced to under 2Mb, and a renewed focus on multimedia

Multimedia

Multimedia is media and content that uses a combination of different content forms. The term can be used as a noun or as an adjective describing a medium as having multiple content forms. The term is used in contrast to media which use only rudimentary computer display such as text-only, or...

libraries.

An alternative to AWT and Swing is the Standard Widget Toolkit

Standard Widget Toolkit

The Standard Widget Toolkit is a graphical widget toolkit for use with the Java platform. It was originally developed by IBM and is now maintained by the Eclipse Foundation in tandem with the Eclipse IDE...

(SWT

Standard Widget Toolkit

), which was originally developed by IBM and now maintained by the Eclipse Foundation

Eclipse Foundation

The Eclipse Foundation is a not-for-profit, member supported corporation that hosts the open-source Eclipse Projects and helps cultivate both an open source community and an ecosystem of complementary products and services...

. It attempts to achieve improved performance and visualization of Java desktop applications by relying on underlying native libraries where possible.
On Windows, Microsoft's .NET is popular desktop development providing both Windows Forms (a lightweight wrapper around the Win32 API), Windows Presentation Foundation, and Silverlight. With the integration of .NET into the Windows platform, .NET apps are first class citizens in the Windows environment with tighter OS integration and native look and feel compared to Java's Swing.

Outside of Windows, Silverlight is portable to the Mac OSX desktop. Mono is also becoming more common in open source and free software systems due to its inclusion on many Linux desktop environments.

Server applications

This is probably the arena in which the two platforms are closest to being considered rivals. Java, through its Java EE (a.k.a. Java Platform Enterprise Edition) platform, and .NET through ASP.NET

ASP.NET

, compete to create web-based dynamic content and applications.

Both platforms are well used and supported in this market, with a bevy of tools and supporting products available for Java EE and .NET. High-end, large-scale, heavy duty solutions tend to opt for Java EE due to higher stability, scalability, and greater availability of senior developers.
For example, for Java: Oracle

Oracle Corporation

Oracle Corporation is an American multinational computer technology corporation that specializes in developing and marketing hardware systems and enterprise software products – particularly database management systems...

included direct support for Java into its database

Oracle database

The Oracle Database is an object-relational database management system produced and marketed by Oracle Corporation....

, while Google

Google

Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...

has used Java to power tools like Gmail

Gmail

Gmail is a free, advertising-supported email service provided by Google. Users may access Gmail as secure webmail, as well via POP3 or IMAP protocols. Gmail was launched as an invitation-only beta release on April 1, 2004 and it became available to the general public on February 7, 2007, though...

. One of the most prominent Java EE projects however is Apache Tomcat

Apache Tomcat

Apache Tomcat is an open source web server and servlet container developed by the Apache Software Foundation...

, which directly competes with Microsoft's own ASP.NET IIS

Internet Information Services

Internet Information Services – formerly called Internet Information Server – is a web server application and set of feature extension modules created by Microsoft for use with Microsoft Windows. It is the most used web server after Apache HTTP Server. IIS 7.5 supports HTTP, HTTPS,...

server.
Some of Sun's current Java-related license agreements for Java EE define aspects of the Java platform as a trade secret, and prohibit the end user from contributing to a third-party Java environment. Specifically, at least one current license for a Sun Java EE development package contains the following terms: "You may make a single archival copy of Software, but otherwise may not copy, modify, or distribute Software." — "Unless enforcement is prohibited by applicable law, you may not decompile, or reverse engineer Software." — "You may not publish or provide the results of any benchmark or comparison tests run on Software to any third party without the prior written consent of Sun." — "Software is confidential and copyrighted." However, while Sun's software is subject to the above license terms, Sun's Java EE API reference has been implemented under an open source license by the JBoss

JBoss

JBoss Application Server is an open-source Java EE-based application server. An important distinction for this class of software is that it not only implements a server that runs on Java, but it actually implements the Java EE part of Java...

and JOnAS

JOnAS

JOnAS is an open-source implementation of the Java EE application server specification, developed and hosted by the ObjectWeb consortium ....

projects.

Microsoft's implementation of ASP.NET

ASP.NET

is not part of the standardized CLI, and while Microsoft's runtime environment and development tools are not subject to comparable secrecy agreements to Java EE, the official Microsoft tools are not open source

Open source

or free software

Free software

Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

, and require Windows servers. However, a cross-platform

Cross-platform

In computing, cross-platform, or multi-platform, is an attribute conferred to computer software or computing methods and concepts that are implemented and inter-operate on multiple computer platforms...

free software ASP.NET 2.0 implementation is part of the Mono project

Mono (software)

Mono, pronounced , is a free and open source project led by Xamarin to create an Ecma standard compliant .NET-compatible set of tools including, among others, a C# compiler and a Common Language Runtime....

(minus webparts and Web Services Enhancements

Web Services Enhancements

Web Services Enhancements is an add-on to the Microsoft .NET Framework which includes a set of classes that implement additional WS-* web service specifications chiefly in areas such as security, reliable messaging, and sending attachments. Web services are business logic components which provide...

Mobile applications

Google's popular Android platform for mobile application is based on Java. Google created its own customised virtual machine called Dalvik to optimise the execution of Java code for mobile devices.

Oracle provides Java ME; a reference implementation for mobile OEM venders. Java ME is made up of various profiles that are subsets of the Java desktop environment with additional libraries targeted at mobile and set top box development. Java ME has a very large base within the mobile phone and PDA

Personal digital assistant

A personal digital assistant , also known as a palmtop computer, or personal data assistant, is a mobile device that functions as a personal information manager. Current PDAs often have the ability to connect to the Internet...

markets, with only the cheapest devices now devoid of a KVM

K virtual machine

The K virtual machine is a virtual machine developed by Sun Microsystems , derived from the Java Virtual Machine specification. The KVM was written from scratch in C. It is designed for small devices and has a small memory footprint. It supports a subset of the features of the higher end JVM...

(a cut down Java Virtual Machine for use on devices with limited processing power). Java software, including many games, is commonplace.

While many feature phones include a JVM, they are not always heavily used by users (particularly in North America). Initially Java applications on most phones typically consisted of menuing systems, small games, or systems to download ringtones etc. However, more powerful phones are increasingly being sold with simple applications pre-loaded, such as translation dictionaries, world clock displays (darkness/light, timezones, etc.) and calculators. Some of these are written in Java, although how often phone owners actually use them is probably unknown.

Microsoft currently ships the .NET Compact Framework

.NET Compact Framework

The Microsoft .NET Compact Framework is a version of the .NET Framework that is designed to run on resource constrained mobile/embedded devices such as personal digital assistants , mobile phones, factory controllers, set-top boxes, etc...

which runs on Windows CE and mobile devices, set-top boxes, and PDAs as well as the Xbox 360. Microsoft also provides the .NET Micro Framework

.NET Micro Framework

The .NET Micro Framework is an Open Source .NET platform for resource-constrained devices with at least 256 KBytes of flash and 64 KBytes of RAM. It includes a small version of the .NET CLR and supports development in C#, Visual Basic .NET, and debugging using Microsoft Visual Studio...

for embedded developers with limited resources. Alternatively, Novell licenses embeddable versions of Mono to 3rd parties to use in their devices and commercially distributes the MonoTouch and MonoDroid framework for iPhone and Android development respectively.

Home entertainment technologies

Java has found a market in digital television, where it can be used to provide software which sits alongside programming, or extends the capabilities of a given Set Top Box. TiVo

TiVo

TiVo is a digital video recorder developed and marketed by TiVo, Inc. and introduced in 1999. TiVo provides an on-screen guide of scheduled broadcast programming television programs, whose features include "Season Pass" schedules which record every new episode of a series, and "WishList"...

, for example, has a facility called "Home Media Engine", which allows JavaTV software to be transmitted to an appropriate TiVo device to complement programming or provide extra functionality (for example, personalized stock tickers on a business news program.)

A variant of Java has been accepted as the official software tool for use on the next generation optical disc technology Blu-ray, via the BD-J

BD-J

BD-J, or Blu-ray Disc Java, is a specification supporting Java ME Xlets for advanced content on Blu-ray Disc and the Packaged Media profile of Globally Executable MHP .BD-J allows bonus content on Blu-ray Disc titles to be far more sophisticated than bonus content provided by standard DVD,...

interactive platform. This will mean that interactive content, such as menus, games, downloadables, etc. on all Blu-ray optical discs will be created under a variant of the Java platform.

Rather than using Java, HD DVD

HD DVD

HD DVD is a discontinued high-density optical disc format for storing data and high-definition video.Supported principally by Toshiba, HD DVD was envisioned to be the successor to the standard DVD format...

(the defunct high definition successor to DVD

DVD

A DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....

) used a technology jointly developed by Microsoft

Microsoft

and Disney

The Walt Disney Company

The Walt Disney Company is the largest media conglomerate in the world in terms of revenue. Founded on October 16, 1923, by Walt and Roy Disney as the Disney Brothers Cartoon Studio, Walt Disney Productions established itself as a leader in the American animation industry before diversifying into...

called HDi that was based on XML

Extensible Markup Language

Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....

, CSS

Cascading Style Sheets

Cascading Style Sheets is a style sheet language used to describe the presentation semantics of a document written in a markup language...

, JavaScript

JavaScript

JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....

, and other technologies that are comparable to those used by standard web browser

Web browser

A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...

s.

The BD-J platform API

Application programming interface

An application programming interface is a source code based specification intended to be used as an interface by software components to communicate with each other...

is more extensive than its iHD rival, with an alleged 8,000 methods and interfaces, as opposed to iHD's 400. And while Microsoft is pushing iHD's XML presentation layer by including it with Windows Vista, iHD is still a newcomer in a market sector where Java technologies are already commonplace.

However, the fact that the HD DVD format has been abandoned in favor of Blu-ray means that HDi is no longer supported on any Optical disc

Optical disc

In computing and optical disc recording technologies, an optical disc is a flat, usually circular disc which encodes binary data in the form of pits and lands on a special material on one of its flat surfaces...

format, making the BD-J format a clear winner.

.NET/Mono

On Windows, Microsoft is promoting .NET as its flagship development platform, by including the .NET runtime in Windows XP Service Pack 2 and 3, Windows Server 2003, Windows Vista, Windows Server 2008 and Windows 7. Microsoft also distributes the Visual Studio Express development environment at no cost.

.NET Framework 3.5 runtime is not pre-installed on versions of Windows prior to Vista SP1, and must be downloaded by the user, which has been criticized because of its large size (65 MB download for .NET 3.5).

While neither .NET nor Mono are installed with Mac OS X out-of-the-box, the Mono project can be downloaded and installed separately, for free, for any Mac user who wants to build and/or run C# and .NET software. As of 13 May 2008, Mono's System.Windows.Forms 2.0 is API complete (contains 100% of classes, methods etc. in Microsoft's System.Windows.Forms 2.0); also System.Windows.Forms 2.0 works natively on Mac OS X.

C# and the CLI are included and used in a number of Linux and BSD based operating systems by way of including the free software Mono Project.

As a result of inclusion of .NET or Mono runtimes in the distributions of Windows and Linux, non-GUI applications that utilize the programming interfaces that are common to both .NET and Mono can be developed in C# or any other .NET language and then deployed across many operating systems and processor architectures using a runtime environment that is available as a part of the operating system's installation. Both Microsoft .NET and the Mono project have complete support for the Ecma- and ISO-standardized C# language and .NET runtime, and many of Microsoft's non-standardized .NET programming interfaces have been implemented or are under development in Mono, but each environment includes many components that have not been implemented in the other.

Java

Starting with XP SP1a, Windows does not ship with a Java runtime environment.

Java comes pre-installed on all new Apple computers since Mac OS X 10.0. Because Apple maintains the Java runtime for Mac OS X, updates are usually one or two versions behind the versions available from Sun for the other operating systems, and versions of Java are usually tied to the specific operating system version, so newer Java versions are usually unavailable for older versions of OS X.

Java comes pre-installed with many commercial Unix flavors, including those from Sun

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...

, IBM

IBM

International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

and Hewlett Packard. As of June 2009, the Fedora 9, Ubuntu 8.04

Ubuntu (operating system)

Ubuntu is a computer operating system based on the Debian Linux distribution and distributed as free and open source software. It is named after the Southern African philosophy of Ubuntu...

, Debian

Debian

Debian is a computer operating system composed of software packages released as free and open source software primarily under the GNU General Public License along with other free software licenses. Debian GNU/Linux, which includes the GNU OS tools and Linux kernel, is a popular and influential...

, Slackware

Slackware

Slackware is a free and open source Linux-based operating system. It was one of the earliest operating systems to be built on top of the Linux kernel and is the oldest currently being maintained. Slackware was created by Patrick Volkerding of Slackware Linux, Inc. in 1993...

extra, Mandriva

Mandriva

Mandriva S.A. is a publicly traded Linux and open source software company with its headquarters in Paris, France and development center in Curitiba, Brazil. Mandriva, S.A...

and OpenSUSE

OpenSUSE

openSUSE is a general purpose operating system built on top of the Linux kernel, developed by the community-supported openSUSE Project and sponsored by SUSE...

distributions are available with OpenJDK, based completely on free

Free software

and open source

Open source

code. Since June 2008, OpenJDK passed all of the compatibility tests in the Java SE 6 JCK

Technology Compatibility Kit

A Technology Compatibility Kit is a suite of tests that at least nominally checks a particular alleged implementation of a Java Specification Request for compliance...

and can claim to be a fully compatible Java 6 implementation. OpenJDK can run complex applications such as Netbeans

NetBeans

NetBeans refers to both a platform framework for Java desktop applications, and an integrated development environment for developing with Java, JavaScript, PHP, Python, Groovy, C, C++, Scala, Clojure, and others...

, Eclipse

Eclipse (software)

Eclipse is a multi-language software development environment comprising an integrated development environment and an extensible plug-in system...

, GlassFish

GlassFish

GlassFish is an open source application server project started by Sun Microsystems for the Java EE platform and now sponsored by Oracle Corporation. The supported version is called Oracle GlassFish Server...

, or JBoss

JBoss

.

The Operating System Distributor License for Java (DLJ) is a Sun initiative to ease distribution issues with operating systems based on OpenSolaris or Linux.

If Java is not installed on a computer by default, it may be downloaded by the user as a web plugin. The web plugin process has been criticized because of the size of the Java plugin. Unlike other plugins the Java download is a full runtime environment, capable of running not just applets, but full applications and dynamic WebStart apps. Because of this the perceived download footprint is larger than some web plugins. However, compared to Java, other popular browser plugins have larger sizes: Java 6 JRE is 13 MB, but Acrobat Reader

Adobe Acrobat

Adobe Acrobat is a family of application software developed by Adobe Systems to view, create, manipulate, print and manage files in Portable Document Format . All members of the family, except Adobe Reader , are commercial software, while the latter is available as freeware and can be downloaded...

is 33 MB, QuickTime

QuickTime

QuickTime is an extensible proprietary multimedia framework developed by Apple Inc., capable of handling various formats of digital video, picture, sound, panoramic images, and interactivity. The classic version of QuickTime is available for Windows XP and later, as well as Mac OS X Leopard and...

19 MB, Windows Media Player

Windows Media Player

Windows Media Player is a media player and media library application developed by Microsoft that is used for playing audio, video and viewing images on personal computers running the Microsoft Windows operating system, as well as on Pocket PC and Windows Mobile-based devices...

25 MB, the .NET Framework 3.0

.NET Framework

The .NET Framework is a software framework that runs primarily on Microsoft Windows. It includes a large library and supports several programming languages which allows language interoperability...

runtime is 54 MB, and the .NET Framework 3.5 runtime is 197 MB (it's a united package for x86, x64 and IA-64, each part has approximately 60 MB).

At the JavaOne

JavaOne

event in May 2007 Sun announced that the deployment issues with Java would be solved in two major updates during the lifespan of Java 6 (the changes will not be held over to Java 7.) These include:

the introduction of a new consumer JRE edition, with an initial 2Mb footprint and the ability to download the remaining 9Mb in sections using an on-demand methodology.
the development of drop-in cross platform JavaScript
JavaScript
JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....

code, which can be used from a web page to install the necessary JRE for a given applet or Rich Internet Application
Rich Internet application
A Rich Internet Application is a Web application that has many of the characteristics of desktop application software, typically delivered either by way of a site-specific browser, via a browser plug-in, independent sandboxes, extensive use of JavaScript, or virtual machines...

to run, if necessary.
an improvement in support for automatically downloading updates to the JRE.
support for pre-loading of the JRE, so applets and applications written in Java start up almost instantaneously.

External links

Moving to C# and the .NET Framework at MSDN
ECMA-335 Common Language Infrastructure (CLI), 4th edition (June 2006) Free download of Ecma CLI standard
ISO/IEC 23271:2006 Common Language Infrastructure (CLI) Partitions I to VI The official ISO/IEC CLI standard

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Standardization

Java

.NET

Community

Desktop applications

Server applications

Mobile applications

Home entertainment technologies

.NET/Mono

Java

See also

External links