What is the difference between public, protected, package-private and private in Java?

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?

Answer 1

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
❌: not accessible