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Java at Oracle

• Homepage
• API Specifications
• The Java Tutorials
• The Java EE 5 Tutorial
• Code Conventions for the Java Programming Language

Java on the Net

• The ServerSide.com
• JARS: The #1 Java Review Service
• Java Boutique
• JavaWorld Magazine
• Wikipedia article

Online-Books

• Java ist auch eine Insel (german)
• Java Programmierhandbuch und Referenz (german)

Codes & Applications

• Examples from "The Java Developers Almanac 1.4"
• Programming tutorials and source code examples
• Open Source Software in Java
• Free Java Applications
• Swing Sightings Index