Table of contents
Permission modifiers: public, protected, default, private
2. Member permission modifier problem
(1) Used in this package: the permission modifiers of members can be public, protected, default
(2) Use across packages: strict requirements
Permission modifiers: public, protected, default, private
| Modifier | This class | This bag | Other buns | other package non-subclass |
|---|---|---|---|---|
| private | √ | × | × | × |
| default | √ | √ (This package is visible to both subcategories and non-subcategories) | × | × |
| protected | √ | √ (This package is visible to both subcategories and non-subcategories) | √ (Other packages are only visible in subclasses) | × |
| public | √ | √ | √ | √ |
External class: public and default
Member variables, member methods, etc.: public, protected, default, private
1. The external class must be public if it is to be used across packages, otherwise it is limited to this package
(1) If the permission modifier of the external class is defaulted, there is no problem in using this package
(2) If the permission modifier of the external class is default, there is a problem with cross-package use
2. Member permission modifier problem
(1) Used in this package: the permission modifiers of members can be public, protected, default
(2) Use across packages: strict requirements
(3) When using across packages, if the permission modifier of the class is default, the member permission modifier > the permission modifier of the class is also meaningless
