Index: /trunk/src/org/openstreetmap/josm/tools/I18n.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/tools/I18n.java	(revision 16011)
+++ /trunk/src/org/openstreetmap/josm/tools/I18n.java	(revision 16012)
@@ -30,4 +30,7 @@
  */
 public final class I18n {
+
+    private static final String CORE_TRANS_DIRECTORY = "/data/trans/";
+    private static final String PLUGIN_TRANS_DIRECTORY = "data/";
 
     /**
@@ -341,5 +344,5 @@
 
     private static URL getTranslationFile(String lang) {
-        return I18n.class.getResource("/data/"+lang.replace('@', '-')+".lang");
+        return I18n.class.getResource(CORE_TRANS_DIRECTORY + lang.replace('@', '-') + ".lang");
     }
 
@@ -417,6 +420,6 @@
         if ("en".equals(loadedCode))
             return;
-        final ZipEntry enfile = new ZipEntry("data/en.lang");
-        final ZipEntry langfile = new ZipEntry("data/"+loadedCode+".lang");
+        final ZipEntry enfile = new ZipEntry(PLUGIN_TRANS_DIRECTORY + "en.lang");
+        final ZipEntry langfile = new ZipEntry(PLUGIN_TRANS_DIRECTORY + loadedCode + ".lang");
         try (
             ZipFile zipFile = new ZipFile(source, StandardCharsets.UTF_8);