Artima Forums: Discussion forums for Java, Jini, J2EE, and object-oriented software design and development.
DevX Discussion Groups: Contains forums on Java and related technologies.
J2me.org: Includes discussion forum for J2ME development and products.
Java Language Forum at Tek-Tips: Technical support forums and mutual help system for computer professionals.
Java Technology Forums: Java Developer Connection topical interactive message boards.
Java Technology Forums: User discussion areas at IBM's developerWorks.
JavaKB: Discussion threads on JavaBeans, Servlets, JDBC and other Java technologies.
P2P - Java: A forum where you can share knowledge with fellow programmers. Java section.
Portlet Discussion: Portlet is a new and emerging technology. This group is created with the objective of discussing portlets and related technology, their usability and problems associated with them.