Java 中的 public、protected、package-private 和 private 有什么区别?

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?

解决方案

The official tutorial may be of some use to you.

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

+ : accessible
blank : not accessible