java SE 1.6各个版本 jdk api
http://www.oracle.com/technetwork/java/javase/downloads/java-archive-downloads-javase6-419409.html
java SE 1.7各个版本 jdk api
http://www.oracle.com/technetwork/java/javase/downloads/java-archive-downloads-javase7-521261.html
java SE 1.8各个版本 jdk api
http://www.oracle.com/technetwork/java/javase/downloads/java-archive-javase8-2177648.html