The href="http://www.oracle.com/technetwork/java/javaee/downloads/java-ee-sdk-7-jdk-7u21-downloads-1956231.html">Java EE 7 SDK provides a comprehensive set of samples for different technologies - both new and updated. They are very nicely documented, runs using Maven + using Cargo, and demonstrate a good usage of the different APIs.
The question I get typically asked is "how do you learn all these APIs and technologies ?".
The SDK samples, reading specifications, and whitboarding with specification leads is indeed a big source of my learning. But I need to write my own code, simple "hello world" style samples that demonstrates point usage of different APIs. I truly believe in "let the code talk" and have given several slide-free code-driven session on Java EE 7 around the world. The source for these talks is about 100+ samples I've written over the past few months.
All of these samples are now available at: href="https://github.com/arun-gupta/javaee7-samples">github.com/arun-gupta/javaee7-samples
They are all Maven-based projects and have no documentation at all. However they are logically arranged by technologies and I've tried to give intuitive names to the directories. I don't intend to write any documentation so please don't ask for it ;-) But at least now you've access to all the samples.
Here is the complete list of samples at this time:
Will continue to add more as I dig into other pieces. I gave a 3-hour presentation explaining some of these samples at UberConf and captured the screen during the session. Those two-part videos are available.