ArrayList中contains，remove方法返回为false的原因

package org.mytest;

import java.util.ArrayList;

/**对ArrayList.remove或者contains的笔记
 * contains,remove时会执行equals()
 * 例子1，删除为false
 * 例子2，删除为true
 * @author ywf
 *
 */
public class test {
public static void main(String[] args) {
    System.out.println("例子1：ArrayList删除Node对象:");
    ArrayList<Node> list = new ArrayList<Node>();
    Node node1 = new Node(1);
    Node node2 = new Node(2);
    list.add(node1);
    list.add(node2);
    System.out.println(list.remove(new Node(1)));
    System.out.println("例子2：ArrayList删除Integer对象:");
    ArrayList<Integer> list1 = new ArrayList<Integer>();
    Integer node11 = new Integer(1);
    Integer node21 = new Integer(2);
    list1.add(node11);
    list1.add(node21);
    System.out.println(list1.remove(new Integer(1)));
}
}
class Node{
    int id;
    public Node(int id){
        this.id = id;
    }
    public boolean equals(Node node){
        return this.id==node.id;
    }
}