Not Serializable Java

Question

I can't figure out why is my class not serializable. As you can see below in my code my class implements Serializable interface.

public class Firm {

PrintWriter out = new PrintWriter(System.out, true);
Scanner sc = new Scanner(System.in);

Set<Worker> workers = new HashSet<>();

boolean saveToFile(){
    String fileName = "text.txt";
    ObjectOutputStream file;
    boolean save = false;
    try{
        file = new ObjectOutputStream(new FileOutputStream(fileName));
        file.writeObject(workers);
        file.close();
        save = true;
    }catch(IOException e){
        e.printStackTrace();
    }
    return save;
}
}

import java.io.Serializable;

public abstract class Worker implements Serializable {//Code

Any ideas how to fix it?

Answer 1

The problem is that the PrintWriter and the Scanner are not serializable; you can't serialize I/O connections like that.

Move those to wherever you're using them, if you need them at all, as local variables. Don't store them in the class.