Just use the idea, imported project or write your own projects using a generic error: Diamond types are not supported at language level '6'
Questions are as follows:
Problem Solving:
1. Click File -> Project Structure check JDK version
2. If you are using a map on SDK 1.8, and then check the modules used in the correct SDK
to modify the image above SDK to OK! If you start the project reported the following error:
Error: the Java: Compilation failed The: Internal the Java Compiler error
here means inconsistency jdk version, cause a compiler error.
Solution:
Click File-> Settings-> Build, Execution, Deployment-> Compiler-> Java Compiler
If you remember to help small series of point like oh ~