Java – static nested subclasses of closed types can still reference private field members. Why?

I've found something vague. With all due respect Suppose we have the following class structure:

public class A
{
    private int privateVar = 1;
    protected int protectedVar = 2;

    static class B extends A
    {
        public int getPrivateVariable()
        {
            return privateVar; //error: Cannot make a static reference to the non-static field memberVariable
        }

        public int getProtectedVariable()
        {
            return protectedVar; //OK: Why?
        }

        public int getPrivateUnfair()
        {
            return super.privateVar; //Why this can be accessed using super which the protected member doesn't require.
        }
    }
}

>Why can static nested classes freely access instance members? > Why are protected and private variables accessed differently? However, if the nested class is a non static inner class, is this not the case?

Edit:

>Why does the keyword super allow access to private members of closed types?

Solution

Because B extends A. you do not have access to a's member variable, you are accessing B's inherited member variable

Because the private field is not inherited, and the protected field is; However, private fields still exist in the superclass and are visible through super because B is nested in a The visibility modifier is not expressed enough to express the same content as accessed through super