Suggested topics, in no particular order and with some dups:

• JAVA N/O, JESS
• Maybe get back to EJB? TOOL Comparison? Eclipse vs. IDEA vs. Netbeans?
• SEAM, Java 6
• Jruby
• op code references
• Jave Native Interface, J2ME
• AOP
• Java 5 concurrency
• Acegi Security, GWT, Case Study of a real world application
• Scala
• JEE Security
• Executable Reqs.
• JPA/Hibernate and Spring, AOP, multithread/Performance testing
• dj java decompiler
• code Obfuscation
• encryption
• java security
• jta
• jms
• concurrency and java 5 (edu.osuego)
• profiling - bottlenecks, loadtests
• workflow jboss pm
• reporting -tools, scheduled, exporting, excel, charts, etc...
• portals
• maven 2 - enterprise version
• soa
• j2me (practical)
• jboss jbpm
• jbi
• spring integrations
• project bootstrapping
• java certifications
• Struts 2