contains（）方法应使用哪些参数？

Question

I don't really understand what parameters I should pass to the contains() method. I have my own class called Name which consists of 2 strings (firstName, secondName). I have created an ArrayList of type Name and 2 Name objects of the same name eg ("Joe, "Bloggs") 2x. So what paremeters do I have to pass to check whether it works. I have correctly overriden the equals method for Name class. This is my main program:

import java.util.ArrayList;

public class EqualsTest {

    public static void main(String[] args) {

        ArrayList<Name> names = new ArrayList<Name>();

        names.add(new Name("Joe", "Bloggs"));
        names.add(new Name("John", "Smith")); //<--
        names.add(new Name("Alan", "Wake"));  //   | the same name
        names.add(new Name("Robert", "High"));//   |
        names.add(new Name("John", "Smith")); //---

        names.contains(Name("Joe", "Bloggs"));      
    }
}

Answer 1

Assuming you've overridden equals correctly in your Name class, it should be:

 if (names.contains(new Name("Joe", "Bloggs"))) {
     ...
 }

Answer 2

You can use

names.contains(new Name("Joe", "Bloggs"));   

But you should override equals() method in Name class to work it as expected.

When ever you need to deal with collection frame work in Java , better to override both equals() and hashCode() method in your classes else you end up with mess.