答群友问：Java静态内部类、普通内部类等的理解

        昨日，某群友在某群里发了一个问题，内容如下：

public class Base {
	private String baseName = "base";
	public Base(){
		callName();
	}
	
	public void callName(){
		System.out.println(baseName);
	}

	 static class Sub extends Base{
		private String baseName = "sub";

		public void callName(){
			System.out.println(Sub.this.baseName);
		}
	}
	
	public static void main(String[] args){
		Base b = new Sub();
	}
}public clas