J2EE frameworks, O/R Mapping, Tomcat, Jetty, Hibernate
XML, XSD, XSLT, XMLBeans, JAXB, StAX,...
Eclipse Plug-ins APIs: Editor, Workbench, EMF, P2, SWT, etc...
Dynamic HTML, AJAX
DBMS, SQL, Sybase, Postgres, mySQL
Agile software development
High Performance Computing
Middleware