Server thread stops when window has been closed

src/main/java/seng302/App.java

@@ -1,7 +1,6 @@
 package seng302;
 
 import javafx.application.Application;
-import javafx.application.Platform;
 import javafx.fxml.FXMLLoader;
 import javafx.scene.Parent;
 import javafx.scene.Scene;
@@ -20,8 +19,9 @@ public class App extends Application
         primaryStage.setMaximized(true);
 
         primaryStage.show();
+
         primaryStage.setOnCloseRequest(e -> {
-            Platform.exit();
+            System.exit(0);
         });
 
     }

src/main/java/seng302/server/ServerThread.java

@@ -98,7 +98,7 @@ public class ServerThread implements Runnable, Observer {
                 boatStatus = BoatStatus.PRESTART;
                 thereAreBoatsNotFinished = true;
             }
-            
+
             BoatSubMessage m = new BoatSubMessage(b.getSourceID(), boatStatus, b.getLastPassedCorner().getSeqID(), 0, 0, b.getEstimatedTimeTillFinish(), b.getEstimatedTimeTillFinish());
             boatSubMessages.add(m);
         }