"The only thing that interferes with my learning is my education." (Albert Einstein)
The Java EE 7 Tutorial is one of the lesser-known gem. It is an extensive tutorial that covers the Java EE platform and its different APIs. The nearly 1.000 pages of the Tutorial might looks a bit daunting for newcomers. But let's be clear, one doesn't have to go through the complete tutorial! The tutorial has been structured in a way to make it easy to learn specific aspects of the platform. And last but not least, the Tutorial also covers more advanced parts of the platform such as JCA for example. In short, the Java EE Tutorial is a great ressource to learn the Java EE platform at large but also learn more specific aspects of Java EE. The tutorial comes in 3 flavours, a free online version and free PDF version but also a 2 tomes based books edition (paper & Kindle version).
The Tutorial also bundles many samples that demonstrate specific API but also a few sample applications that shows how to use and combine the different API's to build a complete application. The samples can be download from the SVN repository but also using the GlassFish update center. The following short screencast shows how to install the samples in NetBeans using the GF update center. It's easy, the samples are just a few clicks away!
It should be mentioned that that the Tutorial and its samples have been recently updated for the release of GlassFish 4.1 (see here for more details).
And if you find any issue on the Tutorial or on one if its samples, please make sure to fill a Jira ticket. That input is valuable to continue to maintain and improve the Java EE Tutorial!