Java permission modifiers (Private, protected, Public, Default, final, static)

Private: Indicates that members are private and can only be accessed in the current class.

Default: no modifiers (default), access within the same package, the access is package-level access.

Protected: Represents protected privileges, embodied in inheritance, which means that subclasses can access protected members of their parent class and other classes within the same package can access protected members.

Public: Indicates that the member is public and accessible to all other classes.

Final: The keyword means final and can modify member methods, member variables, and classes

• Modifier method: Indicates that the method is final and cannot be overridden.

• Modifier variable: Indicates that the variable is constant and cannot be assigned again.

• Modifier class: Indicates that the class is final and cannot be inherited.

• Variables are primitive types: The final modifier means that the data value of the primitive type cannot be changed.

• Variables are reference types: the final modifier means that the address value of a reference type cannot be changed, but the contents of the address can be.

Static: The keyword is static, can modify member methods, member variables

• Non-static member methods

  • Access to static member variables

  • Access to non-static members

  • Access to static member methods

  • Access to non-static member methods

• Static member methods

  • Access to static member variables

  • Access to static member methods

• Summary: Static member methods can only access static members