diff --git a/flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/datastream/WindowedDataStream.java b/flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/datastream/WindowedDataStream.java
index 66dd4f3aebac0fec3680d3edbc8ba529a6082824..6f8c3479360f3356323f325f7099f49fe60a90e0 100644
--- a/flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/datastream/WindowedDataStream.java
+++ b/flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/datastream/WindowedDataStream.java
@@ -349,7 +349,7 @@ public class WindowedDataStream<OUT> {
 	 *            The function that will be applied to the windows.
 	 * @return The transformed DataStream
 	 */
-	public <R> WindowedDataStream<R> mapWindow(WindowMapFunction<OUT, R> windowMapFunction) {
+	public <R> DiscretizedStream<R> mapWindow(WindowMapFunction<OUT, R> windowMapFunction) {
 		return discretize(WindowTransformation.MAPWINDOW.with(clean(windowMapFunction)),
 				getWindowBuffer(WindowTransformation.MAPWINDOW)).mapWindow(windowMapFunction);
 	}
@@ -372,7 +372,7 @@ public class WindowedDataStream<OUT> {
 	 *            The output type of the operator.
 	 * @return The transformed DataStream
 	 */
-	public <R> WindowedDataStream<R> mapWindow(WindowMapFunction<OUT, R> windowMapFunction,
+	public <R> DiscretizedStream<R> mapWindow(WindowMapFunction<OUT, R> windowMapFunction,
 			TypeInformation<R> outType) {
 
 		return discretize(WindowTransformation.MAPWINDOW.with(windowMapFunction),