What are the three Java platform versions?

 Three editions of the Java platform make it easier for software developers, service providers, and device manufacturers to target specific markets. The developerWorks Java technology zone maintains a complete glossary of the standard Java component technologies for the platform editions. Many of these components, optional packages, and extensions — the intricate parts that make up the whole — are available across the three editions.

Java SE (Java Platform, Standard Edition)

Java SE lets you develop and deploy Java applications on desktops and servers, as well as embedded and real-time environments. It includes classes that support the development of Java web services and provides the foundation for Java Platform, Enterprise Edition (Java EE). Java SE 6 is the current version of the Java SE platform. Explore Java SE in the following articles on developerWorks:

• Get started with Java SE 6 in the two-part "Introduction to Java programming" tutorial.


• In "Java technology, IBM style: A new era in Java technology," read about enhancements in the works for subsequent Java SE versions, including value-adds from the IBM Java Technology Center. One such major new functional area is an enhanced API for I/O, the topic of the two-part article "An NIO.2 primer."


• "Monitor and diagnose performance in Java SE 6" describes performance and monitoring enhancements in Java SE 6.


• "Create rich applications with JavaFX Script" introduces a scripting language that runs on top of Java SE 6 and makes it easy to code sophisticated user interfaces.


• The two-part article "Invoke dynamic language dynamically" introduces a Java SE 6 API that enables Java code to execute dynamic scripting code, and vice versa. (See How does Java technology relate to dynamic languages and functional programming? below for more information on using scripting languages with the Java platform.)


• The Taming Tiger series covers Java SE 5, a version that many Java programmers continue to use.

Learn about some of the important component technologies in Java SE:

• Java Foundation Classes (Swing) is a set of class libraries that support building GUIs and graphics functionality for client applications. (To get started, see the tutorial "Introduction to Swing" and "Dynamic interface design with Swing.")


• Java Database Connectivity (JDBC) is an API that lets you access most tabular data sources from within Java code, providing cross-DBMS connectivity to a wide range of SQL databases and access to other tabular data sources, such as spreadsheets or flat files. (See the tutorial "Understanding JDBC.")


• Java Content Repository API is an API for accessing content repositories in Java SE independently of implementation. A content repository is a high-level information-management system that is a superset of traditional data repositories. (See "Introducing the Java Content Repository API.")


• Generics let you define classes with abstract type parameters that you specify at instantiation time. (See "Introduction to generic types in JDK 5.0" and read "Spice up collections with generics and concurrency" to find out how generics make working with collections easier in Java SE 6.)


• Concurrency Utilities are a set of medium-level utilities that provide functionality commonly needed in concurrent programs. (See the tutorial "Concurrency in JDK 5.0.")


• Java API for XML Processing (JAXP) lets Java applications parse and transform XML documents independently of a particular XML processing implementation and gives you the flexibility to swap between XML processors without making application code changes. (See "All about JAXP, Part 1" and "All about JAXP, Part 2.")


• The Java XPath API gives you a way to query XML documents from within Java programs. (See "The Java XPath API.")

Java EE (Java Platform, Enterprise Edition)

The enterprise version of the Java Platform helps you develop and deploy portable, robust, scalable, and secure server-side Java applications. Building on the foundation of Java SE, Java EE provides web services, component-model, management, and communications APIs for implementing enterprise-class service-oriented architecture (SOA) and Web 2.0 applications. Java EE 6 is the latest Java EE version. "Java EE 5: Power and productivity with less complexity" introduces you to version 5 of the Java EE platform — a major overhaul designed to enhance developer productivity through a simpler Java EE programming model (retained in Java EE 6) than in previous versions.
Learn about some of the important component technologies in Java EE:

• JavaServer Faces (JSF) technology provides a programming model that helps you craft web applications by assembling reusable UI components in a page, connecting these components to an application data source, and wiring client-generated events to server-side event handlers. (Explore the JSF 2 fu article series.)


• Enterprise JavaBeans (EJB) technology uses a component model to simplify the development of middleware applications. Java EE 5 revamped the EJB architecture, with the Java Persistence API (JPA) as a prominent feature. JPA provides a standard object-relational mapping solution that bypasses the need to rely on third-party frameworks. (See "Design enterprise applications with the EJB 3.0 Java Persistence API.")


• Portlet Specification defines a set of APIs for Java portal computing, addressing the areas of aggregation, personalization, presentation, and security. (See "What's new in the Java Portlet Specification V2.0 (JSR 286)?")


• Java Message Service (JMS) is an API that enables the development of portable, message-based applications by defining a common set of messaging concepts and programming strategies for all JMS technology-compliant messaging systems. (See the tutorial "Introducing the Java Message Service.")


• JavaServer Pages (JSP) technology lets developers rapidly develop and easily maintain dynamic, platform-independent web pages with separate user interfaces and content generation so designers can change the page layout without altering the dynamic content. (See the tutorial "Introduction to JavaServer Pages technology." JSP technology uses XML-like tags that encapsulate the logic that generates the content for the page. (See the four-part article series "A JSTL primer.")


• Java Servlet technology extends and enhances the reach of web servers by providing a component-based, platform-independent method for building web-based applications without the performance limitations of CGI programs. (The tutorial "Introduction to Java Servlet technology" should get you started.)

Java development for Android

The Java language is the tool of choice for developing applications for Google's mobile platform, Android. The Android runtime uses its own virtual machine, Dalvik — not the JVM that comes with Java ME. See "Introduction to Android development" for an overview.

Java ME (Java Platform, Micro Edition)

Java ME provides an environment for applications running on a broad range of mobile and embedded devices, such as mobile phones, PDAs, TV set-top boxes, and printers. The Java ME platform includes flexible user interfaces, a robust security model, a broad range of built-in network protocols, and extensive support for networked and offline applications that can be downloaded dynamically. Applications based on Java ME specifications are written once for a wide range of devices yet exploit each device's native capabilities.