Why private members of nested class are accessible in outer class [duplicate]

I'm newbie in Java, but faced with interesting problem today. My code is provided below.

class Parent { 
    public void display() 
    { 
        System.out.println(new Child().line); 
    } 

    private class Child {
        private String line = "Greating";
    }
} 
class Program 
{ 
    public static void main(String args[]) 
    { 
        Parent obj = new Parent(); 
        obj.display(); 
    } 
} 

It's also available here. Could anyone clarify why private members of nested class is accessible in outer class? I'm a C# developer and was confused having this behavior.