Friday, September 10, 2010

Free software

Sun announced in JavaOne 2006 that Java would become free and open source software,[19] and on October 25, 2006, at the Oracle OpenWorld conference, Jonathan I. Schwartz said that the company was set to announce the release of the core Java Platform as free and open source software within 30 to 60 days.[20]

Sun released 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 JRE) 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").[21] According to Richard Stallman, this would mean an end to the "Java trap".[22] Mark Shuttleworth called the initial press announcement, "A real milestone for the free software community".[23]

Sun released the source code 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 a free software and open-source license.[24] Some of the encumbered parts turned out to be fairly key parts of the platform such as font rendering and 2D rasterisation, but these were released as open-source later by Sun (see OpenJDK Class library).

Sun's goal is to replace the parts that remain proprietary and closed-source with alternative implementations and make the class library completely free and open source. A third party project called IcedTea has created a completely free and highly usable JDK by replacing encumbered code with either stubs or code from GNU Classpath. IcedTea is currently available on Fedora 7 and Ubuntu.

In June 2008, it was announced that IcedTea6 (as the packaged version of OpenJDK on Fedora 9) has passed the Technology Compatibility Kit tests and can claim to be a fully compatible Java 6 implementation


The source code for Sun's implementations of Java (which is the de-facto reference implementation) has been available for some time, but until recently the license terms severely restricted what could be done with it without signing (and generally paying for) a contract with Sun. As such these terms did not satisfy the requirements of either the Open Source Initiative or theFree Software Foundation to be considered open source or free software, and Sun Java was therefore a proprietary platform.[18]

While several third-party projects (e.g. GNU Classpath and Apache Harmony) created free software partial Java implementations, the sheer size of the Sun libraries combined with the use of clean room techniques meant that their implementations of the Java libraries (the compiler and vm are comparatively small and well defined) were incomplete and not fully compatible. These implementations also tended to be a long way behind Sun's in terms of optimization.

Web server and enterprise use

The Java platform has become a mainstay of enterprise IT development since the introduction of the Enterprise Edition in 1998, in two different ways:
Through the coupling of Java to the web server, the Java platform has become a leading platform for integrating the Web with enterprise backend systems. This has allowed companies to move part or all of their business to the Internet environment by way of highly interactive online environments (such as highly dynamic websites) that allow the customer direct access to the business processes (e.g. online banking websites, airline booking systems and so on). This trend has continued from its initial Web-based start:
The Java platform has matured into an Enterprise Integration role in which legacy systems are unlocked to the outside world through bridges built on the Java platform. This trend has been supported for Java platform support for EAI standards like messaging and web services and has fueled the inclusion of the Java platform as a development basis in such standards as SCA,XAM and others.
Java has become the standard development platform for many companies' IT departments, which do most or all of their corporate development in Java. This type of development is usually related to company-specific tooling (e.g. a booking tool for an airline) and the choice for the Java platform is often driven by a desire to leverage the existing Java infrastructure to build highly intelligent and interconnected tools.
The Java platform has become the main development platform for many software tools and platforms that are produced by third-party software groups (commercial, open source and hybrid) and are used as configurable (rather than programmable) tools by companies. Examples in this category include web servers, application servers, databases, enterprise service buses, BPM tools and content management systems.
Enterprise use of Java has also long been the main driver of open source interest in the platform. This interest has inspired open source communities to produce everything from simple function libraries to program development frameworks (e.g. the Spring Framework, Wicket, Dojo, Hibernate) to open source implementations of standards and tools (e.g. Apache Tomcat, the Glassfish application server, the Mule and ServiceMix ESBs).

Mobile devices

Java ME has become popular in mobile devices, where it competes with Symbian, BREW, and the .NET Compact Framework.

The diversity of mobile phone manufacturers has led to a need for new unified standards so programs can run on phones from different suppliers - MIDP. The first standard was MIDP 1, which assumed a small screen size, no access to audio, and a 32kB program limit. The more recent MIDP 2 allows access to audio, and up to 64kB for the program size. With handset designs improving more rapidly than the standards, some manufacturers relax some limitations in the standards, for example, maximum program size.

Desktop use

According to Sun, the Java Runtime Environment is found on over 700 million PCs.[14] Microsoft has not bundled a Java Runtime Environment(JRE) with its operating systems since Sun Microsystems sued Microsoft for adding Windows-specific classes to the bundled Java runtime environment, and for making the new classes available through Visual J++. A Java runtime environment is bundled with Apple's Mac OS X, and many Linux distributions include the partially compatible free software package GNU Classpath.[15]

Some Java applications are in fairly widespread desktop use, including the NetBeans and Eclipse integrated development environments, and file sharing clients such as LimeWire and Vuze. Java is also used in the MATLAB mathematics programming environment, both for rendering the user interface and as part of the core system.

Version history

The Java language has undergone several changes since JDK (Java Development Kit) 1.0 was released on (January 23, 1996), as well as numerous additions of classes and packages to the standard library. Since J2SE 1.4, the evolution of the Java Language has been governed by the Java Community Process (JCP), which uses Java Specification Requests (JSRs) to propose and specify additions and changes to the Java platform. The language is specified by the Java Language Specification (JLS); changes to the JLS are managed under JSR 901.[8]

JDK 1.1 was released on February 19, 1997. Major additions included an extensive retooling of the AWT event model, inner classes added to the language, JavaBeans and JDBC.

J2SE 1.2 (December 8, 1998) — Codename Playground. This and subsequent releases through J2SE 5.0 were rebranded Java 2 and the version name "J2SE" (Java 2 Platform, Standard Edition) replaced JDK to distinguish the base platform from J2EE (Java 2 Platform, Enterprise Edition) and J2ME (Java 2 Platform, Micro Edition). Major additions included reflection, a Collections framework, Java IDL (an IDLimplementation for CORBA interoperability), and the integration of the Swing graphical API into the core classes. a Java Plug-in was released, and Sun's JVM was equipped with a JIT compiler for the first time.

J2SE 1.3 (May 8, 2000) — Codename Kestrel. Notable changes included the bundling of the HotSpot JVM (the HotSpot JVM was first released in April, 1999 for the J2SE 1.2 JVM), JavaSound, Java Naming and Directory Interface (JNDI) and Java Platform Debugger Architecture (JPDA).

J2SE 1.4 (February 6, 2002) — Codename Merlin. This was the first release of the Java platform developed under the Java Community Process as JSR 59.[9] Major changes included regular expressions modeled after Perl, exception chaining, an integrated XML parser andXSLT processor (JAXP), and Java Web Start.

J2SE 5.0 (September 30, 2004) — Codename Tiger. Originally numbered 1.5, which is still used as the internal version number.[10]Developed under JSR 176, Tiger added a number of significant new language features including the for-each loop, generics, autoboxing andvar-args.[11]

The current version, Java SE 6 (December 11, 2006) — Codename Mustang — is bundled with a database manager, facilitates the use of scripting languages (currently JavaScript using Mozilla's Rhino engine) with the JVM and has Visual Basic language support. As of this version, Sun replaced the name "J2SE" with Java SE and dropped the ".0" from the version number.[12] Other major changes include support for pluggable annotations (JSR 269), lots of GUI improvements, including native UI enhancements to support the look and feel of Windows Vista, and improvements to the Java Platform Debugger Architecture (JPDA) & JVM Tool Interface for better monitoring and troubleshooting

Java SE 7 — Codename Dolphin. The Dolphin Project started in August 2006, with release estimated in September 2010. New builds including enhancements and bug fixes are released approximately weekly.[13]

In addition to the language changes, much more dramatic changes have been made to the Java class library over the years, which has grown from a few hundred classes in JDK 1.0 to over three thousand in J2SE 5.0. Entire new APIs, such as Swing and Java 2D, have been introduced, and many of the original JDK 1.0 classes and methods have been

Java meets the Internet

In June and July 1994, after three days of brainstorming with John Gage, the Director of Science for Sun, Gosling, Joy, Naughton, Wayne Rosing, and Eric Schmidt, the team re-targeted the platform for the World Wide Web. They felt that with the advent of graphical web browsers likeMosaic, the Internet was on its way to evolving into the same highly interactive medium that they had envisioned for cable TV. As a prototype, Naughton wrote a small browser, WebRunner (named after the movie Blade Runner), later renamed HotJava[4].

That year, the language was renamed Java after a trademark search revealed that Oak was used by Oak Technology[6]. Although Java 1.0a was available for download in 1994, the first public release of Java was 1.0a2 with the HotJava browser on May 23, 1995, announced by Gage at theSunWorld conference. His announcement was accompanied by a surprise announcement by Marc Andreessen, Executive Vice President of Netscape Communications Corporation, that Netscape browsers would be including Java support. On January 9, 1996, the JavaSoft group was formed by Sun Microsystems in order to develop the technology

Thursday, September 9, 2010


The Java platform and language began as an internal project at Sun Microsystems in December 1990, providing an alternative to the C++/Cprogramming languages. Engineer Patrick Naughton had become increasingly frustrated with the state of Sun's C++ and C APIs (application programming interfaces) and tools. While considering moving to NeXT, Naughton was offered a chance to work on new technology and thus the Stealth Project was started.

The Stealth Project was soon renamed to the Green Project with James Gosling and Mike Sheridan joining Naughton. Together with other engineers, they began work in a small office on Sand Hill Road in Menlo Park, California. They were attempting to develop a new technology for programming next generation smart appliances, which Sun expected to be a major new opportunity[4].

The team originally considered using C++, but it was rejected for several reasons. Because they were developing an embedded system with limited resources, they decided that C++ demanded too large a footprint and that its complexity led to developer errors. The language's lack of garbage collection meant that programmers had to manually manage system memory, a challenging and error-prone task. The team was also troubled by the language's lack of portable facilities for security, distributed programming, and threading. Finally, they wanted a platform that could be easily ported to all types of devices.

Bill Joy had envisioned a new language combining Mesa and C. In a paper called Further, he proposed to Sun that its engineers should produce an object-oriented environment based on C++. Initially, Gosling attempted to modify and extend C++ (which he referred to as "C++ ++ --") but soon abandoned that in favor of creating an entirely new language, which he called Oak, after the tree that stood just outside his office.

By the summer of 1992, they were able to demonstrate portions of the new platform including the Green OS, the Oak language, the libraries, and the hardware. Their first attempt, demonstrated on September 3, 1992, focused on building a PDA device named Star7[2] which had a graphical interface and a smart agent called "Duke" to assist the user. In November of that year, the Green Project was spun off to becomefirstperson, a wholly owned subsidiary of Sun Microsystems, and the team relocated to Palo Alto, California[5]. The firstperson team was interested in building highly interactive devices, and when Time Warner issued an RFP for a set-top box, firstperson changed their target and responded with a proposal for a set-top box platform. However, the cable industry felt that their platform gave too much control to the user and firstperson lost their bid to SGI. An additional deal with The 3DO Company for a set-top box also failed to materialize. Unable to generate interest within the TV industry, the company was rolled back into Sun.