クライアント-サーブレット間の通信について

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.util.Hashtable;
import java.util.Iterator;

public class MyHash implements Externalizable {
  
  private Hashtable table = new Hashtable();
  private int nufOfEntry;

  public void readExternal(ObjectInput in)
    throws IOException, ClassNotFoundException {
      int num = in.readInt();
      
      for(int i=0; i<num; i++){
        String key = in.readUTF();
        String val = in.readUTF();
        table.put(key, val);
      }      
  }

  public void writeExternal(ObjectOutput out) throws IOException {
    int num = table.size();
    out.writeInt(num);
    for (Iterator iter = table.keySet().iterator(); iter.hasNext(); ) {
      String key = (String) iter.next();
      String val = (String) table.get(key);
      out.writeUTF(key);
      out.writeUTF(val);
    }
  }

  public Object get(Object key) {
    return table.get(key);
  }

  public Object put(Object key, Object value) {
    return table.put(key, value);
  }

}

public class CompressedHashMap extends HashMap{
	private void writeObject(ObjectOutputStream s)throws IOException
	{
		s.defaultWriteObject();
		s.writeInt(size());
		
		ArrayList values = new ArrayList(size());
		for (Iterator i = entrySet().iterator(); i.hasNext(); ) {
			Map.Entry e = (Map.Entry) i.next();
			s.writeObject(e.getKey());//キー値オブジェクトの書き込み
			int index = values.indexOf(e.getValue());
			if(index == -1){
				values.add(e.getValue());
				index = values.size()-1;
			}
			s.writeInt(index);//値オブジェクトへのポインタ(リスト上の位置)を書き込み
		}
		s.writeObject(values.toArray());//値オブジェクトのリストを書き込み
	}	
}

import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.util.Vector;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;

public class AsyncTableUpdate {

	public static void main(String args[])throws Exception{
		JFrame f = new JFrame("Test");
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		JTable t = new JTable(0,10);
		f.getContentPane().add(new JScrollPane(t));
		
		PipedOutputStream pout = new PipedOutputStream();
		PipedInputStream pin = new PipedInputStream(pout);
		final ObjectOutputStream oout = new ObjectOutputStream(pout);
		final ObjectInputStream oin = new ObjectInputStream(pin);
		
		setAsyncWrite(oout);
		setAsyncRead(t,oin);
		f.setSize(600,600);
		f.show();
	}

	public static void setAsyncWrite(final ObjectOutputStream out){
		Thread th = new Thread(){
			public void run(){
				try{
					for(int i = 0 ; i < 2000 ; i++){
						out.writeObject(String.valueOf(i+1));
						Thread.sleep(10);
					}
				}catch(Exception e){}
				finally{
					try{out.close();}catch(Exception e){}
				}
			}
		};
		th.setDaemon(true);
		th.start();
	}


	public static void setAsyncRead(final JTable table,final ObjectInputStream in){
		Thread th = new Thread(){
			public void run(){
				try{
					Vector rowdata = new Vector();
					while(true){
						rowdata.add(in.readObject());
						if(rowdata.size() == table.getColumnCount()){
							DefaultTableModel model = (DefaultTableModel)table.getModel();
							model.addRow(rowdata);
							rowdata = new Vector();
						}
					}
				}
				catch(Exception e){}
				finally{
					try{in.close();}catch(Exception e){}
				}
			}
		};
		th.setDaemon(true);
		th.start();
	}

}