출처는 인텔리J의 Project Structure 에서 발췌
1.3 Plain old java
1.4 assert keyword
1.5 - 'enum' keywrod, generics, autoboxing etc..
1.6 @override in interfaces
1.7 diamonds, arm, multi-catch etc
1.8 lamdas, type annotaions etc.
1.9 modules, private methods in interfaces etc.
x experimental featurs