JAVA class modifier

The modifiers of the Java class are mainly public,default,protected,private,final,abstract,static

Where the external class uses only public,final,abstract or no modifiers, you cannot explicitly add the default

(if additional modifiers are added, eclipse will prompt illegal modifier for the class xxx; Only public, abstract & Final is permitted)

1. Access qualifiers for external classes (public, final,abstract, and default)

Public: Global access, which any class can access. A file can have only one public, and if there is public, the file name needs to be the same as the class name of the public class

Final: Prohibit inheritance

Abstract: Abstraction class

Default: In-Package access (note that you cannot explicitly add the default modifier)

2. Access qualifiers for inner classes (external classes and protected,private,static)

Protected: Only the same file, the same package, or a subclass inheriting it can use the inner class

Private: Except for its outer class and other inner classes of its outer class, it cannot access

Static: Statically internal class

JAVA class modifier