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.
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. 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.Developed under JSR 176, Tiger added a number of significant new language features including the for-each loop, generics, autoboxing andvar-args.
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.
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