Java如何使用instanceOf关键字显示Object类？

在Java中，如何使用instanceOf关键字显示Object类？

下面示例中，显示在displayObjectClass()方法中作为参数传递的对象的类。

package com.zaixian;

import java.util.ArrayList;
import java.util.Vector;

public class displayObjectClass {
    public static void main(String[] args) {
        Object testObject = new ArrayList();
        displayObjectClass(testObject);
    }

    public static void displayObjectClass(Object o) {
        if (o instanceof Vector)
            System.out
                    .println("Object was an instance of the class java.util.Vector");
        else if (o instanceof ArrayList)
            System.out
                    .println("Object was an instance of the class java.util.ArrayList");
        else
            System.out.println("Object was an instance of the " + o.getClass());
    }
}

执行上面示例代码，得到以下结果 -

Object was an instance of the class java.util.ArrayList