Ⅰ、Method Modifiers
Method modifiers include: Annotation, public, protected, private, abstarct, static, final synchronized, native, strictfp
A compile-time error occurs if a method declaration that contains the keyword abstract also contains any one of the keywords: private, static, final, native, strictfp or synchronized.
A compile-time error occurs if method declaration that contains the keyword native also contains strictfp.
At runtime, a machine-code generator of optimizer can "inline" the body of a final method.
Ⅱ、Overriding , Hiding
A compile-time error occurs if an instance method override a static method.
A comiple-time error occurs if a static method hides an instance method.
BUT it permissible for an instance variable to hide a static variable vice versa.