Links

Java and J2EE resources

J2EE
Sun's Java
Blackdown's Java
Java.com
Java.net
Java Lobby
TheServerSide
Java News Feed
JAX (Java Apache XML) Magazine

Open Source J2EE Server

Enhydra and Enhydra Enterprise (based completely on JOnAS J2EE certified server and deliver a lot of good value added things)
JOnAs
JBoss
Geronimo
Glassfish

Open Source Databases

Firebird SQL
MySQL DB
HsqlDB
PostgreSQL

Open Source IDE, Tools and MDA Tools

NetBeans
Eclipse
Ant
ArgoUML
AndroMDA
MTL
ATL