Prevent NPE if value to decode is null (and also shortcut if the value is an empty string)

git-svn-id: https://svn.apache.org/repos/asf/felix/trunk@926111 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/webconsole/src/main/java/org/apache/felix/webconsole/WebConsoleUtil.java b/webconsole/src/main/java/org/apache/felix/webconsole/WebConsoleUtil.java
index 850ee4d..7ff5b55 100644
--- a/webconsole/src/main/java/org/apache/felix/webconsole/WebConsoleUtil.java
+++ b/webconsole/src/main/java/org/apache/felix/webconsole/WebConsoleUtil.java
@@ -350,6 +350,12 @@
      */
     public static String urlDecode( final String value )
     {
+        // shortcut for empty or missing values
+        if ( value == null || value.length() == 0 )
+        {
+            return null;
+        }
+
         try
         {
             return URLDecoder.decode( value, "UTF-8" );