List,Map,Set add方法

import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;


public class MapTest {
	public static void main(String[] args) {
		Map m =new HashMap();
		m.put("1", 2);
		Object i  = m.get("1");
		System.out.println(m.put("1", 3));
		System.out.println(m.get("1"));
		
		Set set = new HashSet();
		set.add("5");
		System.out.println(set.add("5"));
		
		List li = new ArrayList();
		set.add("6");
		System.out.println(set.add("6"));
		
		System.out.println("----Map------------------------");
		m.put(new T("A"), "d");
		m.put(new T("A"), "f");
		m.put(new T("A"), "g");
		
		System.out.println("----set------------------------");
		set.add(new T("A"));
		set.add(new T("A"));
		set.add(new T("A"));
		
		System.out.println("----list------------------------");
		
		li.add(new T("A"));
		li.add(new T("A"));
		li.add(new T("A"));
	}

}

class T{
	private String hashcode;
	public T(String hsCode){
		hashcode = hsCode;
	}
	
	@Override
	public int hashCode() {
		// TODO Auto-generated method stub
		System.out.println("hashcode Function ");
		return hashcode.hashCode();
	}
	
	@Override
	public boolean equals(Object obj) {
		System.out.println("equals Function ");
		// TODO Auto-generated method stub
		return super.equals(obj);
	}
}

 

2
3
false
false
----Map------------------------
hashcode Function 
hashcode Function 
equals Function 
hashcode Function 
equals Function 
equals Function 
----set------------------------
hashcode Function 
hashcode Function 
equals Function 
hashcode Function 
equals Function 
equals Function 
----list------------------------