--- old/jaxp/src/java.xml/share/classes/com/sun/org/apache/xalan/internal/xsltc/runtime/BasisLibrary.java	2015-01-19 14:13:50.814549570 +0300
+++ new/jaxp/src/java.xml/share/classes/com/sun/org/apache/xalan/internal/xsltc/runtime/BasisLibrary.java	2015-01-19 14:13:50.750549571 +0300
@@ -292,7 +292,8 @@
     public static String substringF(String value, double start, double length) {
         if (Double.isInfinite(start) ||
             Double.isNaN(start) ||
-            Double.isNaN(length))
+            Double.isNaN(length) ||
+            length < 0)
             return(EMPTYSTRING);
 
             int istart = (int)Math.round(start) - 1;