solving bug 785 by cloning the WindSources collection

java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/TrackedRace.java

@@ -214,7 +214,7 @@ public interface TrackedRace extends Serializable {
     Iterable<WindSource> getWindSources(WindSourceType type);
 
     /**
-     * Retrieves all wind sources used by this race.
+     * Retrieves all wind sources used by this race. Callers can freely iterate because a copied collection is returned.
      */
     Iterable<WindSource> getWindSources();
 

java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/impl/TrackedRaceImpl.java

@@ -1659,7 +1659,9 @@ public abstract class TrackedRaceImpl implements TrackedRace, CourseListener {
 
     @Override
     public Iterable<WindSource> getWindSources() {
-        return windTracks.keySet();
+        synchronized (windTracks) {
+            return new ArrayList<WindSource>(windTracks.keySet());
+        }
     }
 
     @Override