--- old/src/java.desktop/share/classes/javax/swing/MultiUIDefaults.java	2014-08-25 09:58:57.000000000 +0800
+++ new/src/java.desktop/share/classes/javax/swing/MultiUIDefaults.java	2014-08-25 09:58:57.000000000 +0800
@@ -195,13 +195,13 @@
         Enumeration<?> keys = keys();
         while (keys.hasMoreElements()) {
             Object key = keys.nextElement();
-            sb.append(key + "=" + get(key) + ", ");
+            sb.append(key).append('=').append(get(key)).append(", ");
         }
         int length = sb.length();
         if (length > 1) {
-            sb.delete(length-2, length);
+            sb.delete(length - 2, length);
         }
-        sb.append("}");
+        sb.append('}');
         return sb.toString();
     }
 }