This post visualizes changes between Java EE Standards 5 and 6. The comparison of standards is listed in four sections Web-Services, Web-Container, Enterprise Application technologies and Maintenance. Hope this helps someone.
Web Service related changes
|Java EE 5 (JSR-244)||Java EE 6 (JSR-316)|
|JAX-RPC 1.1 JSR 101||JAX-RPC 1.1|
|Enterprise Web Services 1.2 JSR 109||Enterprise Web Services 1.3 (new version)|
|Web Service Metadata 1.0 JSR 181||Web Service Metadata 1.0|
|Streaming API for XML 1.0 JSR 173||Streaming API for XML 1.0|
|JAX-WS 2.0 JSR 224||JAX-WS 2.2 (new version)|
|JAXB 2.0 JSR 222||JAXB 2.2 (new version)|
|SOAP with Attachments API for Java (SAAJ) JSR 67||Java APIs for XML Messaging 1.3 (new version) spec|
|new! JAX-RS 1.1 JSR 311|
|new! Java API for XML Registries (JAXR 1.0) JSR 93|
The new redesigned Java API for XML Web Services (JAX-WS) is the base or a middle part of a newly Java EE 6 Web service stack. The new stack includes JAX-WS 2.0, JAXB 2.0, and SAAJ 1.3. and is also called "integrated stack". JAX-WS was designed to take place of JAX-RPC. Due this also JSR-109 was updated because it describes run time architecture of JEE Web Services Stack. JAXB which provides an easy way to bind an XML schema to java and vice verse, was updated to.
The SOAP with Attachments API for Java (SAAJ) (also known as Java APIs for XML Messaging (JAXM)) provides a standard way to send XML documents over the Internet from the Java platform and was updated slightly containing now other consolidated standard.
New are JAX-RS, which provides support for RESTful Web services and JAXR which enables pull-parsing API for reading and writing XML documents. Also available in Java SE.
Web Applications related changes
|Java EE 5||Java EE 6|
|JSTL JSR 52||JSTL|
|JavaServer Faces 1.2 JSR 252||JavaServer Faces 2.0 (new version)|
|JavaServer Pages 2.1 JSR 245||JavaServer Pages 2.2 /EL 2.2 (new version)|
|Java Servlet 2.5 JSR 154||Java Servlet 3.0 JSR 315 (new version)|
|new! Debugging Support for Other Languages 1.0 JSR 45|
In Java EE 6 we have updates of all technologies of the Web Container except JSTL. So e.g. Servlet 3.0 improves Servlet concept in pluggability and some ease of development. It's also introduces Async Servlet, and long waited File Uploading!. Also now configuration can be done by annotations.
New a specification of Debugging Support for Other Languages 1.0
This describes standardized tools for correlating Java virtual machine byte code to source code of languages other than the Java programming language, so it would guarantee debugging possibility of everything what runs is JSR-45 certified container.
Enterprise Technologies changes
|Java EE 5||Java EE 6|
|Common Annotations JSR 250||Common Annotations|
|JCA 1.5 JSR 112||JCA 1.6 JSR 322 (new version)|
|JavaMail 1.4||JavaMail 1.4|
|JMS 1.1 JSR 914||JMS 1.1|
|JTA 1.1 JSR 907||JTA 1.1|
|Enterprise JavaBeans 3.0 JSR 220||Enterprise JavaBeans 3.1 JSR 318 (new version)|
|JPA 1.0 JSR 220 (together with EJB 3.0)||JPA 2.0 JSR 317 (new version)|
|new! Contexts and Dependency Injection for Java (Web Beans 1.0) JSR 299|
|new! Dependency Injection for Java 1.0 JSR 330|
|new! Bean Validation 1.0 JSR 303|
|new! Managed Beans 1.0 JSR-316|
In Enterprise Application section we see some important changes and new specifications. Most famous and important is JSR-299 Context and Dependency Injection (CDI) which is there to unify the JavaServer Faces-managed bean component model with the Enterprise JavaBeans component model to simplify the programming model and architecture of web-based applications. Look an Weld Framework as reference implementation to this.
The similar sounding Standard Dependency Injection for Java JSR-330 just define a standard and common known DI like in spring and other frameworks. Look at popular Guice DI-Framework from Google which implements JSR-330.
Bean Validation introduces a very cool annotation based and architecture layer independent Java Bean validation.
There are also some interesting improvements in EJBs. Singleton is a new type and can be only one per container, it is also possible to use @Local Beans (Same VM) without interface. Also JPA 2.0 has advanced query possibilities and validation.
|Java EE 5||Java EE 6|
|J2EE Application Deployment 1.2 JSR 88||J2EE Application Deployment 1.2|
|JavaBeans Activation Framework (JAF) 1.1 JSR 925||JavaBeans Activation Framework (JAF) 1.1|
|J2EE Management 1.0 JSR 77||J2EE Management 1.1 (new version)|
|Java Authorization Contract for Containers 1.1 JSR 115||Java Authorization Contract for Containers 1.3(new version)|
|new! Java Authentication Service Provider Interface for Containers JSR 196|
|new! [JavaSE] JAXP 1.3 JSR 206|
|new! [JavaSE] JDBC 4.0 JSR 221|
|new! [JavaSE] JMX 2.0 JSR 255|
Nothing special to mention here.
Java EE 6 Certified Application Server
Please feel free to correct me or provide additional information.