JAVA语言规范和API网址

Java语言规范: http://docs.oracle.com/javase/specs/

Java API: http://docs.oracle.com/javase/8/docs/api/index.html  (JDK1.8)
　　　　　http://docs.oracle.com/javase/7/docs/api/index.html  (JDK1.7)
http://docs.oracle.com/javase/6/docs/api/index.html  (JDK1.6)