diff --git a/querydsl-core/src/main/java/com/mysema/query/alias/PropertyAccessInvocationHandler.java b/querydsl-core/src/main/java/com/mysema/query/alias/PropertyAccessInvocationHandler.java
index 98f3d988c..3d505fe26 100644
--- a/querydsl-core/src/main/java/com/mysema/query/alias/PropertyAccessInvocationHandler.java
+++ b/querydsl-core/src/main/java/com/mysema/query/alias/PropertyAccessInvocationHandler.java
@@ -28,13 +28,10 @@ import net.sf.cglib.proxy.MethodProxy;
 import org.apache.commons.lang.StringUtils;
 
 import com.mysema.query.types.Expression;
+import com.mysema.query.types.ParametrizedExpression;
 import com.mysema.query.types.Path;
 import com.mysema.query.types.PathMetadata;
 import com.mysema.query.types.PathMetadataFactory;
-import com.mysema.query.types.expr.CollectionExpression;
-import com.mysema.query.types.expr.MapExpression;
-import com.mysema.query.types.path.ListPath;
-import com.mysema.query.types.path.MapPath;
 import com.mysema.util.ReflectionUtils;
 
 /**
@@ -103,8 +100,8 @@ class PropertyAccessInvocationHandler implements MethodInterceptor {
             if (propToObj.containsKey(propKey)) {
                 rv = propToObj.get(propKey);
             } else {
-                PathMetadata<Integer> pm = PathMetadataFactory.forListAccess((ListPath<?, ?>) hostExpression, (Integer) args[0]);
-                Class<?> elementType = ((CollectionExpression<?,?>) hostExpression).getElementType();
+                PathMetadata<Integer> pm = PathMetadataFactory.forListAccess((Path<?>)hostExpression, (Integer) args[0]);
+                Class<?> elementType = ((ParametrizedExpression<?>) hostExpression).getParameter(0);
                 rv = newInstance(elementType, elementType, proxy, propKey, pm);
             }
             aliasFactory.setCurrent(propToExpr.get(propKey));
@@ -114,8 +111,8 @@ class PropertyAccessInvocationHandler implements MethodInterceptor {
             if (propToObj.containsKey(propKey)) {
                 rv = propToObj.get(propKey);
             } else {
-                PathMetadata<?> pm = PathMetadataFactory.forMapAccess((MapPath<?, ?, ?>) hostExpression, args[0]);
-                Class<?> valueType = ((MapExpression<?, ?>) hostExpression).getValueType();
+                PathMetadata<?> pm = PathMetadataFactory.forMapAccess((Path<?>)hostExpression, args[0]);
+                Class<?> valueType = ((ParametrizedExpression<?>) hostExpression).getParameter(1);
                 rv = newInstance(valueType, valueType, proxy, propKey, pm);
             }
             aliasFactory.setCurrent(propToExpr.get(propKey));
diff --git a/querydsl-core/src/main/java/com/mysema/query/types/ParametrizedExpression.java b/querydsl-core/src/main/java/com/mysema/query/types/ParametrizedExpression.java
new file mode 100644
index 000000000..0980a3eb7
--- /dev/null
+++ b/querydsl-core/src/main/java/com/mysema/query/types/ParametrizedExpression.java
@@ -0,0 +1,16 @@
+package com.mysema.query.types;
+
+/**
+ * @author tiwe
+ *
+ * @param <T>
+ */
+public interface ParametrizedExpression<T> extends Expression<T> {
+    
+    /**
+     * @param index
+     * @return
+     */
+    Class<?> getParameter(int index);
+
+}
diff --git a/querydsl-core/src/main/java/com/mysema/query/types/expr/CollectionExpression.java b/querydsl-core/src/main/java/com/mysema/query/types/expr/CollectionExpression.java
index 225a1320e..f1c0f4001 100644
--- a/querydsl-core/src/main/java/com/mysema/query/types/expr/CollectionExpression.java
+++ b/querydsl-core/src/main/java/com/mysema/query/types/expr/CollectionExpression.java
@@ -8,6 +8,7 @@ package com.mysema.query.types.expr;
 import java.util.Collection;
 
 import com.mysema.query.types.Expression;
+import com.mysema.query.types.ParametrizedExpression;
 
 /**
  * CollectionExpression represents java.util.Collection typed expressions
@@ -17,7 +18,7 @@ import com.mysema.query.types.Expression;
  * @param <E>
  * @see java.util.Collection
  */
-public interface CollectionExpression<C extends Collection<E>, E>{
+public interface CollectionExpression<C extends Collection<E>, E> extends ParametrizedExpression<C>{
 
     /**
      * Get an expression for <code>this.contains(child)</code>
diff --git a/querydsl-core/src/main/java/com/mysema/query/types/expr/MapExpression.java b/querydsl-core/src/main/java/com/mysema/query/types/expr/MapExpression.java
index 53c8cbd0e..67533b585 100644
--- a/querydsl-core/src/main/java/com/mysema/query/types/expr/MapExpression.java
+++ b/querydsl-core/src/main/java/com/mysema/query/types/expr/MapExpression.java
@@ -5,7 +5,10 @@
  */
 package com.mysema.query.types.expr;
 
+import java.util.Map;
+
 import com.mysema.query.types.Expression;
+import com.mysema.query.types.ParametrizedExpression;
 
 /**
  * MapExpression represents java.util.Map typed expressions
@@ -16,7 +19,7 @@ import com.mysema.query.types.Expression;
  * @param <V> value type
  * @see java.util.Map
  */
-public interface MapExpression<K, V> {
+public interface MapExpression<K, V> extends ParametrizedExpression<Map<K,V>>{
 
     /**
      * @param key
diff --git a/querydsl-core/src/main/java/com/mysema/query/types/path/CollectionPath.java b/querydsl-core/src/main/java/com/mysema/query/types/path/CollectionPath.java
index c5100ba33..f68fa8340 100644
--- a/querydsl-core/src/main/java/com/mysema/query/types/path/CollectionPath.java
+++ b/querydsl-core/src/main/java/com/mysema/query/types/path/CollectionPath.java
@@ -10,8 +10,8 @@ import java.util.Collection;
 
 import com.mysema.commons.lang.Assert;
 import com.mysema.query.types.Path;
-import com.mysema.query.types.PathMetadata;
 import com.mysema.query.types.PathImpl;
+import com.mysema.query.types.PathMetadata;
 import com.mysema.query.types.Visitor;
 import com.mysema.query.types.expr.CollectionExpressionBase;
 
@@ -84,4 +84,15 @@ public class CollectionPath<E> extends CollectionExpressionBase<Collection<E>,E>
         return pathMixin.getAnnotatedElement();
     }
 
+    @Override
+    public Class<?> getParameter(int index) {
+        if (index == 0){
+            return elementType;
+        }else{
+            throw new IndexOutOfBoundsException(String.valueOf(index));
+        }
+    }
+
+    
+    
 }
diff --git a/querydsl-core/src/main/java/com/mysema/query/types/path/ListPath.java b/querydsl-core/src/main/java/com/mysema/query/types/path/ListPath.java
index e037356d7..31968d2f5 100644
--- a/querydsl-core/src/main/java/com/mysema/query/types/path/ListPath.java
+++ b/querydsl-core/src/main/java/com/mysema/query/types/path/ListPath.java
@@ -158,4 +158,13 @@ public class ListPath<E, Q extends SimpleExpression<E>> extends CollectionExpres
         }
     }
 
+    @Override
+    public Class<?> getParameter(int index) {
+        if (index == 0){
+            return elementType;
+        }else{
+            throw new IndexOutOfBoundsException(String.valueOf(index));
+        }
+    }
+
 }
diff --git a/querydsl-core/src/main/java/com/mysema/query/types/path/MapPath.java b/querydsl-core/src/main/java/com/mysema/query/types/path/MapPath.java
index d375a7519..acdf858a7 100644
--- a/querydsl-core/src/main/java/com/mysema/query/types/path/MapPath.java
+++ b/querydsl-core/src/main/java/com/mysema/query/types/path/MapPath.java
@@ -150,5 +150,16 @@ public class MapPath<K, V, E extends SimpleExpression<V>> extends MapExpressionB
             return constructor.newInstance(pm);
         }
     }
+    
+    @Override
+    public Class<?> getParameter(int index) {
+        if (index == 0){
+            return keyType;
+        }else if (index == 1){    
+            return valueType;
+        }else{
+            throw new IndexOutOfBoundsException(String.valueOf(index));
+        }
+    }
 
 }
diff --git a/querydsl-core/src/main/java/com/mysema/query/types/path/SetPath.java b/querydsl-core/src/main/java/com/mysema/query/types/path/SetPath.java
index e0a513bc9..99f2d46a0 100644
--- a/querydsl-core/src/main/java/com/mysema/query/types/path/SetPath.java
+++ b/querydsl-core/src/main/java/com/mysema/query/types/path/SetPath.java
@@ -83,5 +83,14 @@ public class SetPath<E> extends CollectionExpressionBase<Set<E>,E> implements Pa
     public AnnotatedElement getAnnotatedElement(){
         return pathMixin.getAnnotatedElement();
     }
+    
+    @Override
+    public Class<?> getParameter(int index) {
+        if (index == 0){
+            return elementType;
+        }else{
+            throw new IndexOutOfBoundsException(String.valueOf(index));
+        }
+    }
 
 }
diff --git a/querydsl-core/src/main/java/com/mysema/query/types/query/ListSubQuery.java b/querydsl-core/src/main/java/com/mysema/query/types/query/ListSubQuery.java
index e9029a5db..2684a42d6 100644
--- a/querydsl-core/src/main/java/com/mysema/query/types/query/ListSubQuery.java
+++ b/querydsl-core/src/main/java/com/mysema/query/types/query/ListSubQuery.java
@@ -78,5 +78,14 @@ public final class ListSubQuery<A> extends CollectionExpressionBase<List<A>,A> i
     public Expression<?> as(Expression<?> alias) {
         return SimpleOperation.create(alias.getType(),(Operator)Ops.ALIAS, this, alias);
     }
+    
+    @Override
+    public Class<?> getParameter(int index) {
+        if (index == 0){
+            return elementType;
+        }else{
+            throw new IndexOutOfBoundsException(String.valueOf(index));
+        }
+    }
 
 }