diff --git a/modules/core-databinding/src/main/java/org/apache/tuscany/sca/core/databinding/processor/WrapperJavaInterfaceProcessor.java b/modules/core-databinding/src/main/java/org/apache/tuscany/sca/core/databinding/processor/WrapperJavaInterfaceProcessor.java
index a5526ab031..e72c1b7999 100644
--- a/modules/core-databinding/src/main/java/org/apache/tuscany/sca/core/databinding/processor/WrapperJavaInterfaceProcessor.java
+++ b/modules/core-databinding/src/main/java/org/apache/tuscany/sca/core/databinding/processor/WrapperJavaInterfaceProcessor.java
@@ -95,7 +95,7 @@ private String assignOperationDataBinding(Operation operation) {
         List<DataType> opDataTypes = new LinkedList<DataType>();
 
         opDataTypes.addAll(operation.getInputType().getLogical());
-        opDataTypes.add(operation.getOutputType());
+        opDataTypes.addAll(operation.getOutputType().getLogical());
         for (DataType<DataType> ft : operation.getFaultTypes()) {
             opDataTypes.add(ft.getLogical());
         }