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)