Index: src/main/java/java/util/ResourceBundle.java =================================================================== --- src/main/java/java/util/ResourceBundle.java (revision 535922) +++ src/main/java/java/util/ResourceBundle.java (working copy) @@ -267,8 +267,10 @@ try { Class bundleClass = Class.forName(bundleName, true, loader); - bundle = (ResourceBundle) bundleClass.newInstance(); - bundle.setLocale(locale); + + if (ResourceBundle.class.isAssignableFrom(bundleClass)) { + bundle = (ResourceBundle) bundleClass.newInstance(); + } } catch (LinkageError e) { } catch (Exception e) { } @@ -296,6 +298,8 @@ } catch (IOException e) { } } + } else { + bundle.setLocale(locale); } String extension = strip(locale);