--- a/jaxp/src/java.xml/share/classes/javax/xml/catalog/CatalogUriResolverImpl.java	Wed Jul 05 21:33:32 2017 +0200
+++ b/jaxp/src/java.xml/share/classes/javax/xml/catalog/CatalogUriResolverImpl.java	Tue Apr 12 14:44:23 2016 -0700
@@ -60,6 +60,9 @@
 
     @Override
     public Source resolve(String href, String base) {
+        href = Util.getNotNullOrEmpty(href);
+        base = Util.getNotNullOrEmpty(base);
+
         if (href == null) return null;
 
         CatalogImpl c = (CatalogImpl)catalog;