Index: trunk/src/org/openstreetmap/josm/tools/PlatformHookOsx.java
===================================================================
--- trunk/src/org/openstreetmap/josm/tools/PlatformHookOsx.java	(revision 14367)
+++ trunk/src/org/openstreetmap/josm/tools/PlatformHookOsx.java	(revision 14368)
@@ -205,5 +205,5 @@
     @Override
     public void openUrl(String url) throws IOException {
-        Runtime.getRuntime().exec("open " + url);
+        Runtime.getRuntime().exec(new String[]{"open", url});
     }
 
Index: trunk/src/org/openstreetmap/josm/tools/PlatformHookWindows.java
===================================================================
--- trunk/src/org/openstreetmap/josm/tools/PlatformHookWindows.java	(revision 14367)
+++ trunk/src/org/openstreetmap/josm/tools/PlatformHookWindows.java	(revision 14368)
@@ -188,5 +188,5 @@
     @Override
     public void openUrl(String url) throws IOException {
-        Runtime.getRuntime().exec("rundll32 url.dll,FileProtocolHandler " + url);
+        Runtime.getRuntime().exec(new String[]{"rundll32", "url.dll,FileProtocolHandler", url});
     }