Interesting server framework: http://www.destinystar.com/
Compare with Avalon: http://jakarta.apache.org/avalon/

Java Wallet Documentation | http://java.sun.com/products/commerce/docs/index.html

Java(TM) 2 Platform, Enterprise Edition Blueprints | http://java.sun.com/j2ee/blueprints/ | How Sun thinks you should build big applications using Java

OpenEJB - an open-source ejb container from the author of the o'reilly ejb book | http://openejb.exolab.org/

xslt -> PDF print formatter | http://xml.apache.org/fop/

Log4j - a java logging and tracing package | http://www.log4j.org/

jBoss -- open source EJB server - Eliot Polk recommends | http://www.jboss.org/

Decimal arithmetic for Java - 1.08 | http://www2.hursley.ibm.com/decimalj/

Advanced Programming for the Java 2 Platform | http://developer.java.sun.com/developer/onlineTraining/Programming/JDCBook/index.html

Sun's JDBC Technology Site | http://java.sun.com/products/jdbc/

EJB Servers | http://www.mgm-edv.de/ejbsig/ejbservers.html | A list of commercial and free EJB servers

JOnAS | http://www.evidian.com/jonas/index.htm | JOnAS Open Application Server for EJB, looks like it was written by a research group inside Groupe Bull and now it's a spin-off called Evidian.

jGuru: Enterprise JavaBeans(TM) Fundamentals | http://developer.java.sun.com/developer/onlineTraining/EJBIntro/EJBIntro.html | An online course in Enterprise JavaBeans at Sun's web site

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

ICU4J - International Components for Unicode for Java | http://oss.software.ibm.com/icu4j/

JUnit, Testing Resources for Extreme Programming | http://www.junit.org/

Java(TM) Technology & XML | http://java.sun.com/xml/

the serverside.com - your middleware portal | http://www2.theserverside.com/

KopiSusu - a GPL java compiler | http://www.klomp.org/KopiSusu/

Implementing the Singleton Pattern in Java - Rod Waldhoff | http://members.tripod.com/rwald/java/articles/Singleton_in_Java.html

JSwat - Graphical Java Debugger | http://www.bluemarsh.com/java/jswat/