Java SE 6 (or JDK 6), codenamed Mustang, was released on December 11, 2006. Sun replaced J2SE with Java SE, and dropped the .0 from the version number.
JDK 6 New Language Features
No new language features were introduced in JDK 6.
JDK 6 Library Changes
Improved Web Service support through JAX-WS (JSR 224)
JDBC 4.0 Support (JSR 221)
Java Compiler API (JSR 199)
Scripting Language Support (JSR 223)
JDK 6 Other New Features
Performance improvement for the core platform and Swing
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