--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/JSType.java	Fri Feb 27 14:33:47 2015 +0100
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/JSType.java	Mon Mar 02 14:33:55 2015 +0100
@@ -311,7 +311,7 @@
             return JSType.BOOLEAN;
         }
 
-        if (obj instanceof String || obj instanceof ConsString) {
+        if (isString(obj)) {
             return JSType.STRING;
         }
 
@@ -349,7 +349,7 @@
             return JSType.BOOLEAN;
         }
 
-        if (obj instanceof String || obj instanceof ConsString) {
+        if (isString(obj)) {
             return JSType.STRING;
         }
 
@@ -455,8 +455,7 @@
                obj == ScriptRuntime.UNDEFINED ||
                obj instanceof Boolean ||
                obj instanceof Number ||
-               obj instanceof String ||
-               obj instanceof ConsString;
+               isString(obj);
     }
 
    /**
@@ -577,7 +576,7 @@
             return num != 0 && !Double.isNaN(num);
         }
 
-        if (obj instanceof String || obj instanceof ConsString) {
+        if (isString(obj)) {
             return ((CharSequence)obj).length() > 0;
         }
 
@@ -628,6 +627,15 @@
     }
 
     /**
+     * Returns true if object represents a primitive JavaScript string value.
+     * @param obj the object
+     * @return true if the object represents a primitive JavaScript string value.
+     */
+    public static boolean isString(final Object obj) {
+        return obj instanceof String || obj instanceof ConsString;
+    }
+
+    /**
      * JavaScript compliant conversion of integer to String
      *
      * @param num an integer