Index: /trunk/src/org/openstreetmap/josm/data/Preferences.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/data/Preferences.java	(revision 5976)
+++ /trunk/src/org/openstreetmap/josm/data/Preferences.java	(revision 5977)
@@ -1344,4 +1344,11 @@
             // Ignore all exceptions
         }
+        // Workaround to fix another Java bug
+        // Force Java 7 to use old sorting algorithm of Arrays.sort (fix #8712).
+        // See Oracle bug database: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7075600 
+        // and http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6923200
+        if (Main.pref.getBoolean("jdk.Arrays.useLegacyMergeSort", !Version.getInstance().isLocalBuild())) {
+            updateSystemProperty("java.util.Arrays.useLegacyMergeSort", "true");
+        }
     }