http://java.sun.com/

Java FAQ:
http://www.afu.com/javafaq.html

Sun's Java mailing lists:
http://archives.java.sun.com/

Sun's Java Developer Connection:
http://developer.java.sun.com/

Java Community Process:
http://www.jcp.org/

JavaOne conference:
http://java.sun.com/javaone/

JavaWorld:
http://www.javaworld.com/

http://www.theserverside.com/

http://www.javalobby.org/

http://www.jguru.com/

O'Reilly's OnJava.com:
http://www.onjava.com/

http://www.javaranch.com/

http://www.jspinsider.com/

Sun's Java Blueprints:
http://java.sun.com/blueprints/

http://www.jboss.org/

http://www.junit.org/

http://www.jdom.org/

http://www.dom4j.org/

Apache's XML parsers: Xerces-J, Crimson
http://xml.apache.org/

Sun's XML technologies for Java (JAXP, JAXM, JAXB, ...):
http://java.sun.com/xml/

Apache's Jakarta projects (Tomcat servlet engine, Ant, etc):
http://jakarta.apache.org/

http://jakarta.apache.org/jmeter/

http://www.exolab.org/

http://www.openejb.org/

http://www.openjms.org/

http://openjmx.sourceforge.net/

http://www.enhydra.org/

http://www.javaperformancetuning.com/

IBM's Java technology:
http://www.ibm.com/java/

IBM's AlphaWorks:
http://www.alphaworks.ibm.com/

http://www.servlets.com (Jason Hunter)

O'Reilly's Java books:
http://java.oreilly.com/

http://xdoclet.sourceforge.net/

http://beust.com/ejbgen/

Logging:
http://jakarta.apache.org/log4j/docs/index.html

news:comp.lang.java.programmer

Borland's JBuilder:
http://www.borland.com/jbuilder/

Intellij IDEA:
http://www.intellij.com/

WebGain's Visual Cafe:
http://www.webgain.com/

NetBeans IDE:
http://www.netbeans.org/

Sun Forte for Java:
http://www.sun.com/forte/ffj/

http://www.eclipse.org/

JSwat debugger:
http://www.bluemarsh.com/java/jswat/

http://www.bluej.org/

http://www.castor.org/

http://zeus.enhydra.org/

http://www.jini.org/

http://www.jxta.org/

http://www.jxul.org/

http://www.jtrix.org/

http://www.beanshell.org/

http://www.aspectj.org/

The Mind Electric:
http://www.themindelectric.com/ - the company behind GLUE

BEA Weblogic:
http://www.bea.com/

http://www.artima.com/java/index.html

WROX mailing lists:
http://p2p.wrox.com/

DevelopMentor mailing lists:
http://discuss.develop.com/

Comparison of C# and Java:
http://www.25hoursaday.com/CsharpVsJava.html

http://www.jedit.org/

http://www.jext.org/

open source SyncML server:
http://sync4j.sourceforge.net/

GNU Compiler for Java (GCJ):
http://gcc.gnu.org/java/

http://wbemservices.sourceforge.net/

Jetty (Java HTTP Servlet server):
http://jetty.mortbay.com/

Jigsaw (HTTP server, written in Java):
http://www.w3.org/Jigsaw/

Caucho Resin:
http://www.caucho.com/

Bytecode Engineering Library (BCEL):
http://bcel.sourceforge.net/ and http://jakarta.apache.org/bcel/

http://www.jvalue.org/

http://www.jython.org/

http://objectbridge.sourceforge.net/

http://jgrinder.sourceforge.net/

http://www.ozone-db.org/

http://www.antlr.org/

http://www.sablecc.org/

Java glossary:
http://www.mindprod.com/gloss.html

Research Java VM's / JVM Research:

Intel's Open Runtime Platform
http://orp.sourceforge.net/

http://www.usenix.org/events/jvm01/

http://www.usenix.org/events/jvm02/

http://research.sun.com/jtech/

http://www.japhar.org/

http://www.sablevm.org/

http://www-106.ibm.com/developerwork...rary/jalapeno/

IBM's Jikes RVM (Research Virtual Machine):
http://www-124.ibm.com/developerworks/oss/jikesrvm/

http://www.research.ibm.com/jalapeno/

http://www.gnu.org/software/classpath/

http://www.javagrande.org/

http://www.kaffe.org/

http://wonka.acunia.com/

HP MicroChai VM:
http://devnet.hp.com/projects/microchaivm/