Abstract class with nested class, is this possible?

Question

If I write an abstract class, then nest a class in the abstract class, will I have access to its methods in any subclasses of the abstract class? I cannot find the answer anywhere..

Answer 1

Of course, access modifiers on inner classes obey the same rules as on fields and methods. It does not matter whether your class is abstract or concrete, as long as the nested class is either public, protected or the subclass is in the same package and the inner class is package private (default access modifier), the subclass will have access to it.

public abstract class AbstractTest {

    // all subclasses have access to these classes
    public class PublicInner {}
    protected class ProtectedInner {}

    // subclasses in the same package have access to this class
    class PackagePrivateInner {}

    // subclasses do not have access to this class
    private class PrivateClass {}

}

Answer 2

class Abstract {
    modifier1 class Nested { modifier2 int i = 0; }
    Abstract() {
        Nested n = new Nested();
        n.i = 1;
    }
}

class Sub extends Abstract {
    Sub() {
        Nested n = new Nested();
       // have access as long you not choose "private"
       // for `modifier1` or `modifier2`:
        n.i = 5;
    }
}