Index: modules/pvm/src/main/java/org/jbpm/pvm/internal/script/EnvironmentBindings.java
===================================================================
--- modules/pvm/src/main/java/org/jbpm/pvm/internal/script/EnvironmentBindings.java	(revision 6433)
+++ modules/pvm/src/main/java/org/jbpm/pvm/internal/script/EnvironmentBindings.java	(working copy)
@@ -22,6 +22,7 @@
 package org.jbpm.pvm.internal.script;
 
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Map;
 import java.util.Set;
 
@@ -32,9 +33,10 @@
 
 /**
  * @author Tom Baeyens
+ * @author Huisheng Xu
  */
 public class EnvironmentBindings implements Bindings {
-  
+
   protected EnvironmentImpl environment;
 
   public EnvironmentBindings(String[] readContextNames, String writeContextName) {
@@ -54,38 +56,38 @@
   }
 
   public void putAll(Map< ? extends String, ? extends Object> toMerge) {
-    throw new UnsupportedOperationException();
+    //
   }
 
   public Object remove(Object key) {
-    throw new UnsupportedOperationException();
+    return null;
   }
 
   public void clear() {
-    throw new UnsupportedOperationException();
+    //
   }
 
   public boolean containsValue(Object value) {
-    throw new UnsupportedOperationException();
+    return false;
   }
 
   public Set<java.util.Map.Entry<String, Object>> entrySet() {
-    throw new UnsupportedOperationException();
+    return Collections.EMPTY_SET;
   }
 
   public boolean isEmpty() {
-    throw new UnsupportedOperationException();
+    return true;
   }
 
   public Set<String> keySet() {
-    throw new UnsupportedOperationException();
+    return Collections.EMPTY_SET;
   }
 
   public int size() {
-    throw new UnsupportedOperationException();
+    return 0;
   }
 
   public Collection<Object> values() {
-    throw new UnsupportedOperationException();
+    return Collections.EMPTY_SET;
   }
 }