diff --git a/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/StreamFunctionProperties.java b/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/StreamFunctionProperties.java
index bc2879207..79130df62 100644
--- a/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/StreamFunctionProperties.java
+++ b/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/StreamFunctionProperties.java
@@ -73,6 +73,9 @@ public class StreamFunctionProperties {
 	}
 
 	public void setDefinition(String definition) {
+		if (definition == null) {
+			return;
+		}
 		this.composeFrom = definition.startsWith("|");
 		this.composeTo = definition.endsWith("|");
 		this.definition = this.composeFrom ? definition.substring(1)