SE 6.0 does not have significant language syntax changes like 5.0 did, but there are some very interesting and useful additions being added to the next release of Java, codenamed Mustang, which is currently available for download in beta.
Sun Developer Network have a concise list of the major changes on their site here.
Most interesting of the additions is the support for developing Web Service clients and exposing code as callable Web Services, through support using annotations to mark up Web Services, and the addition of XML parsing and object to XML mapping APIs previously only available in Java EE.
Danny Coward has an example of how you use these annotations in his blog, and it really cannot be any simpler that this. Mustang has includes an Http endpoint service for Web Services, so with another 1 line of code you can publish your Web Service, all within Mustang.
Other interesting additions:
- an integrated Java Database, based on Apache Derby.
- Desktop integration APIs, for example SysTray integration on Windows
- Monitoring and Management facilities
- pluggable annotation support