Index: C:/User/Work/workspace/ognl/src/java/ognl/SimpleNode.java
===================================================================
--- C:/User/Work/workspace/ognl/src/java/ognl/SimpleNode.java	(revision 139)
+++ C:/User/Work/workspace/ognl/src/java/ognl/SimpleNode.java	(working copy)
@@ -44,7 +44,7 @@
     protected OgnlParser    parser;
 
     private boolean         constantValueCalculated;
-    private boolean         hasConstantValue;
+    private volatile boolean hasConstantValue;
     private Object          constantValue;
 
     public SimpleNode(int i) {
@@ -162,10 +162,11 @@
         context.setCurrentNode(this);
         if (!constantValueCalculated) {
             constantValueCalculated = true;
-            hasConstantValue = isConstant(context);
-            if (hasConstantValue) {
+            boolean constant = isConstant(context);
+            if (constant) {
                 constantValue = getValueBody(context, source);
             }
+            hasConstantValue = constant;
         }
         return hasConstantValue ? constantValue : getValueBody(context, source);
     }