question on understanding “UserInfo user1 = (UserInfo) ois.readObject();”

[cake naiyou]

I am learning java, and studying the following example from sun.com.

public class UserInfo implements Serializable {
   String name = null;

   public UserInfo(String name) {
   this.name = name;
 }

 public void printInfo() {
    System.out.println("The name is: "+name);
 }
}

import java.io.*;
import java.util.Date;

public class ReadInfo {

public static void main(String argv[]) throws Exception {
    FileInputStream fis = new FileInputStream("name.out");
    ObjectInputStream ois = new ObjectInputStream(fis);

    UserInfo user1 = (UserInfo) ois.readObject();
    UserInfo user2 = (UserInfo) ois.readObject();

    user1.printInfo();
    user2.printInfo();
    ois.close();
    fis.close();
 }
 }

I am having question regarding the ReadInfo.java. In specific, I do not know how to understand the code of line UserInfo user1 = (UserInfo) ois.readObject(); Especially, what is the functionality of “UserInfo” in the parenthesis. What is the relationship between (UserInfo) and ols.readObject( ).

[fred rosenberger]

it is called a cast.

the method is defined to return an Object reference. That means it can return ANY object. We're telling the compiler that we really know it is returning a UserInfo reference, so we're sort of forcing it to consider it as such.