Access Private members of Inner classes

One class cannot access the private members of another class even in Parent-Child relation.

class First
{
	static private int x=10;
}
class Second extends First 
{
	public static void main(String[] args) 
	{
		System.out.println("First - x : " + First.x);  // Error : private access
	}
}

Outer class can access the private functionality of inner class.

class Outer
{
	class Inner
	{
		private void fun()
		{
			System.out.println("Inner class private fun...");
		}
	}
	public static void main(String args[])
	{
		System.out.println("Outer class main");
		new Outer().new Inner().fun();
	}
}

Inner class access private members of outer class as well.

class Outer
{
	private static int x=10;
	class Inner
	{
		private void fun()
		{
			System.out.println("Outer - x value : " + Outer.x);
		}
	}
	public static void main(String args[])
	{
		new Outer().new Inner().fun();
	}
}

Non-static members of outer class including private, can be accessed from the inner class as follows:

            <Outer_class_name>.this.<Outer_class_non-static-member>

class Outer
{
	private int x ;
	Outer(int x)
	{
		this.x = x ;
	}
	class Inner
	{
		int x ;
		Inner(int x)
		{
			this.x = x ;
		}
		private void method()
		{
			System.out.println("Outer's x val : "+Outer.this.x);
			System.out.println("Inner's x val : "+this.x);
		}
	}
	public static void main(String args[ ])
	{
		Outer obj1 = new Outer(100);
		Outer.Inner obj2 = obj1.new Inner(200);
		obj2.method();
	}
}