在 Java 中，public、 protected、 package-private 和 private 之间有什么区别？

Question

In Java, are there clear rules on when to use each of access modifiers, namely the default (package private), public, protected and private, while making class and interface and dealing with inheritance?

转载于:https://stackoverflow.com/questions/215497/what-is-the-difference-between-public-protected-package-private-and-private-in

Answer 1

The official tutorial may be of some use to you.

            │ Class │ Package │ Subclass │ Subclass │ World
            │       │         │(same pkg)│(diff pkg)│ 
────────────┼───────┼─────────┼──────────┼──────────┼────────
public      │   +   │    +    │    +     │     +    │   +     
────────────┼───────┼─────────┼──────────┼──────────┼────────
protected   │   +   │    +    │    +     │     +    │         
────────────┼───────┼─────────┼──────────┼──────────┼────────
no modifier │   +   │    +    │    +     │          │    
────────────┼───────┼─────────┼──────────┼──────────┼────────
private     │   +   │         │          │          │    

+ : accessible
blank : not accessible