Object的getClass()方法

先来代码

package test;

public class TestGetClass {
	public static void main(String[] args) {
		A a1 = new A();
		Object o1 = new A();
		
		System.out.println(a1.getClass().getSimpleName());
		System.out.println(o1.getClass().getSimpleName());
		System.out.println(o1.getClass().getSuperclass().getSimpleName());
	}
}

class A {
	
}

结果贴出来：
A
A
Object

原因很简单，就是因为getClass()方法返回的是运行时的类名。一下是getClass()源码的部分注释：
       The actual result type is {@code Class<? extends |X|>}
     * where {@code |X|} is the erasure of the static type of the
     * expression on which {@code getClass} is called.