Usage of API documented as @since1.6+
File ->Project Structure->Project Settings -> Modules -> your Module name -> Sources -> Language Level->choose the one which you needed.
Error:java: Compilation failed: internal java compiler error
set中java complier 设置的问题 ，项目中有人用jdk1.6 有人用jdk1.7 版本不一样 会一起这个错误 进行如下操作：