Why protected can be access in same Package without inheritance in java? [duplicate]

问题

This question already has answers here:

Why does the “protected” modifier in Java allow access to other classes in same package? (6 answers)

Closed 3 years ago.

  Modifier        Class     Package   Subclass  World
  public          Y         Y         Y         Y
  protected       Y         Y         Y         N
  no modifier     Y         Y         N         N
  private         Y         N         N         N

  public class a {
  protected int x;
  }

  public class b {
        b() {
              a A=new a();
              A.x=9;//why we can access this field ?
        }
  }

please help my to know the specific work of protected in Java

回答1:

Why? Because that's how the Java programming language was designed. There's not much more to it.

Something that is protected is accessible from

• the class itself,
• classes in the same package (doesn't matter if they are subclasses or not),
• subclasses (doesn't matter if they are in the same package or not).

This is different from C++, but Java is not C++, so it doesn't necessarily work in the same way.

来源：https://stackoverflow.com/questions/13309609/why-protected-can-be-access-in-same-package-without-inheritance-in-java