Index: trunk/src/org/openstreetmap/josm/io/audio/JavaFxMediaPlayer.java
===================================================================
--- trunk/src/org/openstreetmap/josm/io/audio/JavaFxMediaPlayer.java	(revision 12461)
+++ trunk/src/org/openstreetmap/josm/io/audio/JavaFxMediaPlayer.java	(revision 12462)
@@ -56,5 +56,5 @@
 
     @Override
-    public void play(Execute command, State stateChange, URL playingUrl) throws AudioException, IOException {
+    public synchronized void play(Execute command, State stateChange, URL playingUrl) throws AudioException, IOException {
         try {
             final URL url = command.url();
@@ -86,5 +86,5 @@
 
     @Override
-    public void pause(Execute command, State stateChange, URL playingUrl) throws AudioException, IOException {
+    public synchronized void pause(Execute command, State stateChange, URL playingUrl) throws AudioException, IOException {
         if (mediaPlayer != null) {
             try {
@@ -103,11 +103,11 @@
 
     @Override
-    public double position() {
-        return mediaPlayer.getCurrentTime().toSeconds();
+    public synchronized double position() {
+        return mediaPlayer != null ? mediaPlayer.getCurrentTime().toSeconds() : -1;
     }
 
     @Override
-    public double speed() {
-        return mediaPlayer.getCurrentRate();
+    public synchronized double speed() {
+        return mediaPlayer != null ? mediaPlayer.getCurrentRate() : -1;
     }