Index: trunk/src/org/openstreetmap/josm/data/cache/JCSCacheManager.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/cache/JCSCacheManager.java	(revision 11168)
+++ trunk/src/org/openstreetmap/josm/data/cache/JCSCacheManager.java	(revision 11169)
@@ -6,4 +6,5 @@
 import java.io.IOException;
 import java.nio.channels.FileLock;
+import java.util.Arrays;
 import java.util.Properties;
 import java.util.logging.Handler;
@@ -82,4 +83,5 @@
         jcsLog.setUseParentHandlers(false);
         // we need a separate handler from Main's, as we downgrade LEVEL.INFO to DEBUG level
+        Arrays.stream(jcsLog.getHandlers()).forEach(jcsLog::removeHandler);
         jcsLog.addHandler(new Handler() {
             final SimpleFormatter formatter = new SimpleFormatter();