Some reformatting.

src/StockExchange/BuyOrder.java

@@ -1,17 +1,15 @@
 package StockExchange;
 
-public class BuyOrder  extends Order implements Comparable<Order>{
+public class BuyOrder extends Order implements Comparable<Order> {
 
+    @Override
+    public int compareTo(Order o) {
 
-	
-	public int compareTo(Order o){
-
-		if (o.limit < limit)
-		{
+        if (o.limit < limit) {
             //System.out.println("return 1");
             return -1;
         }
-		if (o.limit > limit){
+        if (o.limit > limit) {
             //System.out.println("return -1");
             return +1;
         }

src/StockExchange/Exchange.java

@@ -28,7 +28,7 @@ public class Exchange extends Thread {
     }
 
     // Here we store the list of quote receivers
-    TreeSet<QuoteReceiver> qrlist = new TreeSet<QuoteReceiver>();
+    TreeSet<QuoteReceiver> qrlist = new TreeSet();
 
     public void AddQuoteReceiver(QuoteReceiver qr) {
         qrlist.add(qr);
@@ -52,7 +52,7 @@ public class Exchange extends Thread {
     long lastsize;
 
     // Order orderlist[];
-    TreeSet<BuyOrder> bid = new TreeSet<BuyOrder>();
+    TreeSet<BuyOrder> bid = new TreeSet();
     TreeSet<SellOrder> ask = new TreeSet<SellOrder>();
 
     private final Semaphore available = new Semaphore(1, true);

src/StockExchange/Order.java

@@ -1,41 +1,44 @@
 package StockExchange;
 
+public abstract class Order implements Comparable<Order> {
 
-public abstract class Order implements Comparable<Order>{
-	public long timestamp=0;
+    /**
+     * when
+     */
+    public long timestamp = 0;
     public long size;
     public double limit;
 //	long time;
-	double money=0;
+    double money = 0;
 //	public long shares=0;
-	public long id=0;
-	public Account account=null;
-	
+    public long id = 0;
+    public Account account = null;
 
     enum OrderStatus {
-		open,executed,canceled
+        open, executed, canceled
     }
 
-	OrderStatus status=OrderStatus.open;
+    OrderStatus status = OrderStatus.open;
 
-	public long getAge(){
-		if (timestamp==0)
+    public long getAge() {
+        if (timestamp == 0) {
             return 0;
-		return System.currentTimeMillis()-timestamp;
+        }
+        return System.currentTimeMillis() - timestamp;
     }
 
-	String format_limit(){
-		if (limit <0.0){
+    String format_limit() {
+        if (limit < 0.0) {
             return "n.a.";
         }
-		return String.format("%.2f",limit); 
+        return String.format("%.2f", limit);
     }
 
-	String format_size(){
+    String format_size() {
         return String.format("%d", size);
     }
 
-	Order(){
+    Order() {
 
     }
 }

src/sesim/SeSim.java

@@ -5,6 +5,8 @@
  */
 package sesim;
 
+import StockExchange.*;
+
 /**
  *
  * @author tube
@@ -15,6 +17,10 @@ public class SeSim {
      * @param args the command line arguments
      */
     public static void main(String[] args) {
+        Exchange se = new StockExchange.Exchange();
+        se.start();
+        
+        
         // TODO code application logic here
     }