[SpringBoot]报错 Inferred type 'S' for type parameter 'S' is not within its bound;

problem causes:

　　SpringBoot version of the problem, SpringBoot new features of 2.0.

 

Solution:

　　1, a modified version, reduced SpringBoot 1.5.x;

　　2, modify the code:

1 before the modification:　　return userRepository.findOne (ID);
 2 modified:　　return . UserRepository the findById (ID) .orElse ( null ) ;