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

Question

  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

Solution

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.

Comments

[Jesper]

Because that's just how the Java programming language was designed.

[Rohit Jain]

James Gosling has not yet joined SO. Wait till he registers. Then only you will get the exact reason.

[Marko Topolnik]

Consider this: if it didn't work that way, how would you make a set of tightly coupled classes in the same package, that also exported some of their internals to outside subclasses? You'd need even more modifiers for that, making the language unnecessarily complex.

[Marko Topolnik]

@aioobe The main point for me is that both "public" and "protected" signal public API -- some parts of API are designed to be used by extending library's classes. Seen this way, it would be really bad if you couldn't export something to your package "friends" without it becoming public API.

[motaz99]

Thank you <br>So in Java if we have on packet we can't let subclasses access spacial field and prevent other classes in same packet to access it