deserialize EOF Exception, Serialize may write file improperly

Question

package thegreatestrpgevermade;
import java.util.HashMap;
import java.lang.reflect.*;
import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.io.Externalizable;
import javax.swing.Action;
import javax.swing.AbstractAction;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.io.ObjectInputStream;
import java.io.FileOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
public class Room implements Externalizable
{
    static Room room;
     HashMap<Integer,ParentObject> ParentObjectMap ;
     int roomNumber ;
     int width  ;
     int height ;
     int idNumber ;
    static  ActionClass actionClass;
    static  JFrame creationWindow;
    static  JPanel creationPanel;
    static  JButton addObjectButton;
    static  JButton removeObjectButton;
    static  JButton finalizeRoomButton;
    static JTextField classNameField;
    static  JTextField xSpawnField;
    static  JTextField ySpawnField;
    static  JTextField argument3Field;
    static  JTextField numberOfArgumentsField;
    static  JTextField roomNumberField;
    static  JTextField roomWidthField;
    static  JTextField roomHeightField;

    public Room()
    {
     HashMap<Integer,ParentObject> ParentObjectMap = new HashMap();;
     int roomNumber=0 ;
     int width =0 ;
     int height =0;
     int idNumber =0;
    }
    static Object StringToObj (String name, Object[] argArray, int numArgs)
    {
        try
        {
        Class o = Class.forName(name);
        Class argTypes[] = new Class[numArgs];
        //System.out.println("A");
        for(int I = 0; I<numArgs ; I ++)
        {
            argTypes[I] = Class.forName(argArray[I].getClass().getName());//.Type;
            if (Class.forName(argArray[I].getClass().getName()) == Integer.class)
            {
                argTypes[I] = Integer.TYPE;
            }
            //System.out.println(argArray[I].getClass().getName());
        //argTypes[1] = Integer.TYPE;
        }
        Constructor constructor = o.getConstructor(argTypes);
        //Object arguments[] = new Object[numArgs];
        //System.out.println("C");
        //arguments[0] = A;
        //arguments[1] = B;
        Object newObject = constructor.newInstance(argArray);
        //System.out.println("D");
        return newObject;
        }

        catch(ClassNotFoundException cnfe)
        {
            System.out.println("Class not found exception ");
            System.exit(1);
        }
        catch(NoSuchMethodException nsme)
        {
            System.out.println("No Such Method Exception");
            System.exit(1);
        }
        catch(InstantiationException instExcep)
        {
            System.out.println("Instantiation Exception");
            System.exit(1);
        }
        catch(IllegalAccessException iae)
        {
            System.out.println("Illegal Access Exception");
            System.exit(1);
        }
        catch(InvocationTargetException ite)
        {
            System.out.println("Invocation target exception");
            System.exit(1);
        }
        //so , sort through an array of all the sub classes of parent object, 
        //or maybe all the classes in the package, and test their getName
        //against the argument until it comes out right, then return that class. 
        System.out.println("String to Obj is broken");
        return null;
    }
    class ActionClass implements ActionListener
    {
       public void actionPerformed (ActionEvent e)
       {
           if(e.getSource() == addObjectButton)
           {
               Object[] arguments = new Object[Integer.parseInt(numberOfArgumentsField.getText())];
               arguments[0] = Integer.parseInt(xSpawnField.getText());
               arguments[1] = Integer.parseInt(ySpawnField.getText());
               //arguments[2] = idNumber;

               ParentObject placeHolder = (ParentObject)StringToObj("thegreatestrpgevermade." +
                       classNameField.getText(), arguments,Integer.parseInt(numberOfArgumentsField.getText()));
               placeHolder.IDNUMBER = idNumber;
               idNumber ++;
               ParentObjectMap.put(new Integer(idNumber),placeHolder);
               System.out.println("idnumber :" +placeHolder.IDNUMBER);
           }
           if(e.getSource() == removeObjectButton)
           {
              System.out.println(ParentObjectMap.get(0).spriteDirectory);
              System.out.println("removeObjectButton Pressed");                     
           }
           if(e.getSource() == finalizeRoomButton)
           {
               try
               {
                   roomNumber = Integer.parseInt(roomNumberField.getText());
                   width = Integer.parseInt(roomWidthField.getText());
                   height = Integer.parseInt(roomHeightField.getText());
                   FileOutputStream fos = new FileOutputStream("C:\\thegreatestrpgevermade\\room" 
                           + roomNumber +".ser");
                   ObjectOutputStream oos = new ObjectOutputStream(fos);
                   System.out.println("Finalize: room line 152");
                   oos.writeObject(room);
                   System.out.println("Finalize: room line 154");
                   oos.flush();
                   oos.close();
               }
               catch(IOException ioe)
               {
                   System.out.println("io exception room");
                   System.exit(1);
               } 
           }
       }
    }
    public  void InitializeCreationMode()
    {
       room = new Room();
       ParentObjectMap = new HashMap();
       actionClass = new ActionClass();
       creationWindow = new JFrame();
       creationPanel = new JPanel();
       addObjectButton = new JButton("Add Object");
       removeObjectButton = new JButton("Remove Object");
       finalizeRoomButton = new JButton("Finalize Room");
       classNameField = new JTextField("Class Name",20);
       xSpawnField = new JTextField("X Coordinate(arg1)" , 20);
       ySpawnField = new JTextField("Y Coordinate(arg2)" , 20);
       argument3Field = new JTextField("Argument 3" , 20);
       numberOfArgumentsField = new JTextField("Number Of Arguments" , 20);
       roomNumberField = new JTextField("Room Number" , 20);
       roomWidthField = new JTextField("Room Width" , 20);
       roomHeightField = new JTextField("Room Height" , 20);
       creationWindow.setSize(300,400);
       creationWindow.setResizable(false);
       creationWindow.setLocation(0,0);
       creationWindow.add(creationPanel);
       creationWindow.setDefaultCloseOperation(creationWindow.EXIT_ON_CLOSE);
       creationPanel.setSize(300,400);
       creationPanel.add(addObjectButton);
       creationPanel.add(removeObjectButton);
       creationPanel.add(finalizeRoomButton);
       creationPanel.add(roomNumberField);
       creationPanel.add(roomWidthField);
       creationPanel.add(roomHeightField);
       creationPanel.add(classNameField);
       creationPanel.add(numberOfArgumentsField); 
       creationPanel.add(xSpawnField);
       creationPanel.add(ySpawnField);
       creationPanel.add(argument3Field);
       addObjectButton.addActionListener(actionClass);
       removeObjectButton.addActionListener(actionClass);
       finalizeRoomButton.addActionListener(actionClass);
       creationWindow.setVisible(true);
       //im thinking ID numbers can't stay random.
        //so basically, say HERO hits ENEMY. if ENEMY gets hit, it gives 
        //HERO its ID number which can be put into the hashmap to modify
        // ENEMY'S health. 
    }
    public void readExternal(ObjectInput in)
    {
        try
        {

            idNumber = in.readInt();
            width = in.readInt();
            height = in.readInt();
            roomNumber = in.readInt();
           // ParentObjectMap = (HashMap)in.readObject();
        }
        catch(IOException ioe)
        {
            System.out.println(ioe.toString());
            ioe.printStackTrace();
        }
        catch(ClassNotFoundException cnfe)
        {
            System.out.println("cnfe exception readExternal");
        }
    }
    public void writeExternal(ObjectOutput out)
    {
        try
        {
            System.out.println("Checkpoint 1 writeExternal");
            out.writeInt(idNumber);
            System.out.println("Checkpoint 2 writeExternal: width:" + width);
            out.writeObject(width);
            System.out.println("Checkpoint 3 writeExternal : width:" + width);
            out.writeInt(height);
            System.out.println("Checkpoint 4 writeExternal");
            out.writeInt(roomNumber);
            System.out.println("Checkpoint 5 writeExternal");
            //out.writeObject(ParentObjectMap);
        }
        catch(IOException ioe)
        {
            System.out.println(ioe.toString());
            ioe.printStackTrace();
        }

    }
    /*public static void main(String[] args)
    {   
       room = new Room();
       room.InitializeCreationMode();
    }*/

}

The other class is MainClass. Ill include the relevant snippet.

            FileInputStream fis = new FileInputStream("C:\\thegreatestrpgevermade\\room0.ser");
            ObjectInputStream ois = new ObjectInputStream(fis);          
            room = (Room)ois.readObject();
 //           room = new Room();
            room.InitializeCreationMode();
            System.out.println("Room Width: " +room.width);

The stack trace is this:

java.io.EOFException
at java.io.DataInputStream.readInt(DataInputStream.java:392)
at java.io.ObjectInputStream$BlockDataInputStream.readInt(ObjectInputStream.java:2820)
at java.io.ObjectInputStream.readInt(ObjectInputStream.java:971)
at thegreatestrpgevermade.Room.readExternal(Room.java:220)
at java.io.ObjectInputStream.readExternalData(ObjectInputStream.java:1837)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1796)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
at thegreatestrpgevermade.MainClass.main(MainClass.java:176)

The Initialize creation mode method creates a jwindow with buttons and fields to assign values to width, height,etc. The action class listens to its buttons and the finalize button serializes the fields. Something is wrong with the serialization. printing out width at any point gives a zero. I have no idea why.

Answer 1

Assuming the question is kind of stated in your title, the answer is yes, the file wasn't written correctly. But you don't need all this. Change it to implement Serializable instead of Externalizable, and remove the readExternal() and writeExternal() methods.