Trackpoint trackpoint4 = new Trackpoint(4);
competition.addTrackpoint(trackpoint1);
competition.addTrackpoint(trackpoint2);
competition.addTrackpoint(trackpoint3);
competition.addTrackpoint(trackpoint4);
PersistenceManager pm = pmf.getPersistenceManager();
//store the graph defined above in the datastore
pm.currentTransaction().begin();
//make persistent the competition