History of Java 2 (incl. code names)

JDK 1.1 (released on Feb 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 (Dec 8, 1998) — codename Playground.
  Major additions included reflection, a Collections framework, Java IDL (an IDL implementation 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 1.2 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)]

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, JNDI and JPDA.

J2SE 1.4 (Feb 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 and XSLT processor (JAXP), and Java Web Start.

J2SE 5.0 or 1.5 (Sep 30, 2004) — codename Tiger.
 Developed under JSR 176, Tiger added a number of significant new language features including the for-each loop, generics, autoboxing and var-args.

Java SE 6 (Dec 11, 2006) — codename Mustang --> current version
 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. 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 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]

Glossary:
JNDI - Java Naming and Directory Interface
JPDA - Java Platform Debugger Architecture
JDBC - Java DataBase Connectivity
JAXP - Java XML Parsing
J2SE - Java 2 Standard Edition
J2EE - Java 2 Enterprise Edition
J2ME - Java 2 Mobile Edition
JVM - Java Virtual Machine
JCP - Java Community Process

Web project - folder structure

Web Deployment Descriptor

web.xml file

JavaSource (or src/java)

Contains the project's Java source code for classes, beans, and servlets. When these resources are added to a Web project, they are automatically compiled and the generated files are added to the WEB-INF/classes directory. The contents of the source directory are not packaged in WAR files unless an option is specified when a WAR file is created.

imported_classes folder

This folder may be created during a WAR import, and contains class files that do not have accompanying source. The imported_classes folder is a Java classes folder; Java classes folders can also be created using the Web project Java Build Path properties page.

WebContent (or web) folder

The mandatory location of all Web resources, including HTML, JSP, graphic files, and so on. If the files are not placed in this directory (or in a subdirectory structure under this directory), the files will not be available when the application is executed on a server. The Web content folder represents the contents of the WAR file that will be deployed to the server. Any files not under the Web content folder are considered development-time resources (for example, .java files, .sql files, and .mif files), and are not deployed when the project is unit tested or published.

META-INF

This directory contains the MANIFEST.MF file, which is used to map class paths for dependent JAR files that exist in other projects in the same Enterprise Application project. An entry in this file will update the run-time project class path and Java build settings to include the referenced JAR files.

theme

The suggested directory for cascading style sheets (css) and other style-related objects.

WEB-INF

Based on the Sun Microsystems Java Servlet 2.3 Specification, this directory contains the supporting Web resources for a Web application, including the web.xml file and the classes and lib directories.

/classes

This directory is for servlets, utility classes, and the Java compiler output directory. The classes in this directory are used by the application class loader to load the classes. Folders in this directory will map package and class names, as in: /WEB-INF/classes/com/mycorp/servlets/MyServlet.class.This is generated while a build happens. Do not place any .class files directly into this directory. The .class files are placed in this directory automatically when the Java compiler compiles Java source files that are in the Java Resources directory. Any files placed directly in this directory will be deleted by the Java compiler when it runs.

/lib

The supporting JAR files that your Web application references. Any classes in .jar files placed in this directory will be available for your Web application. In short, jar's file would be in classpath.

Libraries

The supporting JAR files that your Web application references. This folder mirrors the content of the lib folder. In addition, Web Library Projects, which are "virtual" JAR files that do not physically reside in the Web project, but are associated with Java projects elsewhere in your workspace, are included in this folder. They are packaged with your project when you export the application's WAR file.

 A library entry on the Java build path will remain there unless the actual JAR file is deleted from the WEB-INF/lib folder. If you remove a library path entry but not the JAR file, the library entry will be re-added to the path automatically.

[Ultimate Reference: http://java.sun.com/blueprints/code/projectconventions.html ]