diff --git a/src/performancetest/java/teetime/examples/experiment01/LegacyCollectorSink.java b/src/performancetest/java/teetime/examples/experiment01/LegacyCollectorSink.java
index a87507ced802ed93465a2d0ae1eaca772da2b38c..1f24ecf0208813d57e8b68efed479ccd17a32e27 100644
--- a/src/performancetest/java/teetime/examples/experiment01/LegacyCollectorSink.java
+++ b/src/performancetest/java/teetime/examples/experiment01/LegacyCollectorSink.java
@@ -46,13 +46,14 @@ public class LegacyCollectorSink<T> {
 		System.out.println("size: " + this.elements.size());
 	}
 
-	protected void execute(final T element) {
+	protected Object execute(final T element) {
 		this.elements.add(element);
 
 		if ((this.elements.size() % this.threshold) == 0) {
 			System.out.println("size: " + this.elements.size());
 		}
 
+		return new Object();
 		// if (this.elements.size() > 90000) {
 		// // System.out.println("size > 90000: " + this.elements.size());
 		// }
diff --git a/src/performancetest/java/teetime/examples/experiment01/LegacyObjectProducer.java b/src/performancetest/java/teetime/examples/experiment01/LegacyObjectProducer.java
index 909537a39f1ad2b743008a7ad00f7767355c8651..4c87ce8f7e54ec4c41160ff13f3cf96a3e8bd2d1 100644
--- a/src/performancetest/java/teetime/examples/experiment01/LegacyObjectProducer.java
+++ b/src/performancetest/java/teetime/examples/experiment01/LegacyObjectProducer.java
@@ -52,6 +52,10 @@ public class LegacyObjectProducer<T> {
 	}
 
 	protected T execute() {
+		if (this.numInputObjects == 0) {
+			return null;
+		}
+
 		T newObject = this.inputObjectCreator.create();
 		this.numInputObjects--;