I have just taken and passed the Sun Certified Web Component Developer exam. I believe the studying process itself is the important value. Through going over the Java Servlets & JSP specification you get to know the less visible parts of this technology and acquire the professional skills required for becoming a valuable developer.

Stable Values in Java (JEP 502): Deferred Immutability with JVM Trust
Explore Stable Values – a new Java 25 upcoming feature (JEP 502) enabling lazy initialization with immutable performance and JVM-level optimizations.