--- a/nashorn/src/jdk/nashorn/internal/runtime/ScriptingFunctions.java	Thu Jun 26 15:36:15 2014 +0200
+++ b/nashorn/src/jdk/nashorn/internal/runtime/ScriptingFunctions.java	Fri Jun 27 10:47:44 2014 +0200
@@ -107,8 +107,8 @@
 
         if (file instanceof File) {
             f = (File)file;
-        } else if (file instanceof String) {
-            f = new java.io.File((String)file);
+        } else if (file instanceof String || file instanceof ConsString) {
+            f = new java.io.File(((CharSequence)file).toString());
         }
 
         if (f == null || !f.isFile()) {

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/script/basic/JDK-8048505.js	Fri Jun 27 10:47:44 2014 +0200
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * Read fully parameter test
+ *
+ * @test
+ * @option -scripting
+ * @run
+ */
+
+var str = __FILE__;
+var first = readFully(str);
+print(typeof str);
+
+var str2 = __FILE__.substring(0,5);
+var str3 = __FILE__.substring(5);
+print(typeof str2);
+print(typeof str3);
+
+var cons = str2 + str3;
+print(typeof cons);
+
+var second = readFully(cons);
+
+var f = new java.io.File(str);
+print(typeof f);
+var third = readFully(f);
+
+print(first.length() == second.length());
+print(first.length() == third.length());
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/script/basic/JDK-8048505.js.EXPECTED	Fri Jun 27 10:47:44 2014 +0200
@@ -0,0 +1,7 @@
+string
+string
+string
+string
+object
+true
+true