3. Consider the following Java class named Staff. import java.util.ArrayList; public class Staff ( private String username; private String pwd; private String id; private String name; private ArrayList carList; public Staff (String u, String p, String i, String n) { } username = u; pwd pi id=1; name = n; carList = new ArrayList (); public String getUserName() { } return username; public String getPassword() { } return pwd; public String getId() { } return id; public String getName() { } return name; public ArrayList getAll Registered Cars () { return carList; } public boolean is Registered Car (String plateNum) { for (Car element: carList) { } if (element.getPlateNum().equals (plateNum)) return true; return false; } public void unregister Car (String plateNum) { for (int i=0; i