关于TreeSet的排序对于删除操作的影响

        TreeSet<Node> list = new TreeSet<>();
        Node n1 = new Node(1);
        Node n2 = new Node(2);
        Node n3 = new Node(3);
        Node n4 = new Node(4);
        Node n5 = new Node(5);

package examples.base;
import java.util.TreeSet;
public class TestTreeSet {
	public static void main(String[] args) {
		TreeSet<Node> list = new TreeSet<>();
		Node n1 = new Node(1);
		Node n2 = new Node(2);
		Node n3 = new Node(3);
		Node n4 = new Node(4);
		Node n5 = new Node(5);
		Node n = new Node(5);
		list.add(n1);
		list.add(n2);
		list.add(n3);
		list.add(n4);
		list.add(n5);
		list.add(n);
		System.out.println(list);
		System.out.println(list.higher(n3));
		n1.id = 5;
		if(list.remove(n1)){
			System.out.println("true");
		}
		
		list.add(n1);
		System.out.println(list);
		
	}
	
	protected static class Node implements Comparable<Node>
	{
		public int id;
		private int __id;
		private static int ID = 1;
		public Node(int id) {
			this.id = id;
			this.__id = ID++;
		}
		
		@Override
		public String toString() {
			return "Node("+__id+") "+id;
		}
		
		@Override
		public int compareTo(Node o) {
			if(o.id>id)
				return 1;
			else if(o.id == id)
				return 0;
			else
				return -1;
						
		}
	}
}

[Node(5) 5, Node(4) 4, Node(3) 3, Node(2) 2, Node(1) 1]
Node(2) 2
true
[Node(1) 5, Node(4) 4, Node(3) 3, Node(2) 2, Node(1) 5]