Index: modeshape-jcr/src/main/java/org/modeshape/jcr/JcrI18n.java
===================================================================
--- modeshape-jcr/src/main/java/org/modeshape/jcr/JcrI18n.java	(revision 2488)
+++ modeshape-jcr/src/main/java/org/modeshape/jcr/JcrI18n.java	(working copy)
@@ -58,6 +58,7 @@ public final class JcrI18n {
     public static I18n unableToFindNodeTypeDefinitionsOnClasspathOrFileOrUrl;
     public static I18n unableToFindResourceOnClasspathOrFileOrUrl;
     public static I18n fileMustExistAndBeReadable;
+    public static I18n invalidJcrUrl;
 
     public static I18n rootNodeHasNoParent;
     public static I18n rootNodeIsNotProperty;
Index: modeshape-jcr/src/main/java/org/modeshape/jcr/JcrRepositoryFactory.java
===================================================================
--- modeshape-jcr/src/main/java/org/modeshape/jcr/JcrRepositoryFactory.java	(revision 2488)
+++ modeshape-jcr/src/main/java/org/modeshape/jcr/JcrRepositoryFactory.java	(working copy)
@@ -417,6 +417,10 @@ public class JcrRepositoryFactory implements RepositoryFactory {
      * @return the URL version of {@code jcrUrl} if {@code jcrUrl} is a valid URL, otherwise null
      */
     private URL urlFor( String jcrUrl ) {
+        if (jcrUrl == null || jcrUrl.isEmpty()) {
+            throw new IllegalStateException(JcrI18n.invalidJcrUrl.text(jcrUrl));
+        }
+
         try {
             return new URL(jcrUrl.toString());
         } catch (MalformedURLException mue) {
Index: modeshape-jcr/src/main/resources/org/modeshape/jcr/JcrI18n.properties
===================================================================
--- modeshape-jcr/src/main/resources/org/modeshape/jcr/JcrI18n.properties	(revision 2488)
+++ modeshape-jcr/src/main/resources/org/modeshape/jcr/JcrI18n.properties	(working copy)
@@ -48,6 +48,7 @@ errorLoadingNodeTypeDefintions = Error loading CND file "{0}": {1}
 unableToFindNodeTypeDefinitionsOnClasspathOrFileOrUrl = Unable to find the node type definition file "{0}" on the classpath, as a relative or absolute file, or resolve as a URL
 unableToFindResourceOnClasspathOrFileOrUrl = Unable to find "{0}" on the classpath, as a relative or absolute file, or resolve as a URL
 fileMustExistAndBeReadable = The file at "{0}" must exist and be readable
+invalidJcrUrl = A valid JCR URL must be provided to use this method.  "{0}" is not a valid JCR URL.  Please consult the ModeShape Reference Guide for information on providing a valid JCR URL.
 
 rootNodeHasNoParent = The root node has no parent node
 rootNodeIsNotProperty = The root path "/" refers to the root node, not a property