About Java EE
From My Limbic Wiki
API
Web Service
JAX-WS
Used for developing webservices. This api is meant for SOAP based services As per Roy Fielding's theory, REST services should be stateless. So SOAP is the only choice.
JAX-RS
JPA
JAXP
XML
StaX
Streaming API for XML (StAX) This Java API is an event-driven, pull parsing API for reading and writing XML documents. This java API will enable you to create bidirectional XML parsers that are fasts, relatively easy to program and have a light memory footprint.
JAXB
Java Architecture for XML Binding
JAXP
Java API for XML Processing (JAXP)
SAAJ
SOAP with Attachments API for Java