Java ArrayListSerialise

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

//ArrayListSerialise
public class A {
    public static void main(String[] args) throws IOException,
            ClassNotFoundException {
        ObjectOutputStream outStream = new ObjectOutputStream(
                new FileOutputStream("personnelList.dat"));
        ArrayList<Personnel> staffListOut = new ArrayList<>();
        ArrayList<Personnel> staffListIn = new ArrayList<>();
        Personnel[] staff = { new Personnel(123456, "Smith", "John"),
                new Personnel(234567, "Jones", "Sally Ann"),
                new Personnel(999999, "Black", "James Paul") };
        for (int i = 0; i < staff.length; i++)
            staffListOut.add(staff[i]);
        outStream.writeObject(staffListOut);
        outStream.close();
        ObjectInputStream inStream = new ObjectInputStream(new FileInputStream("personnelList.dat"));
        int staffCount = 0;
        try {
            staffListIn = (ArrayList<Personnel>) inStream.readObject();
            // The compiler will issue a warning for the
            // above line, but ignore this!
            for (Personnel person : staffListIn) {
                staffCount++;
                System.out.println("\nStaff member " + staffCount);
                System.out.println("Payroll number: " + person.getPayNum());
                System.out.println("Surname: " + person.getSurname());
                System.out.println("First names: " + person.getFirstNames());
            }
            System.out.println("\n");
        } catch (EOFException eofEx) {
            System.out.println("\n\n*** End of fi le ***\n");
            inStream.close();
        }
    }
}

class Personnel implements Serializable {
    private long payrollNum;
    private String surname;
    private String firstNames;

    public Personnel(long payNum, String sName, String fNames) {
        payrollNum = payNum;
        surname = sName;
        firstNames = fNames;
    }

    public long getPayNum() {
        return payrollNum;
    }

    public String getSurname() {
        return surname;
    }

    public String getFirstNames() {
        return firstNames;
    }

    public void setSurname(String sName) {
        surname = sName;
    }
}