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------------------------