From d5c67218becf1996dc77519f95ead2c63d6a9955 Mon Sep 17 00:00:00 2001
From: spencergibb <spencer@gibb.us>
Date: Mon, 14 Sep 2020 17:08:27 -0400
Subject: [PATCH] Adds null check

---
 .../gateway/mvc/config/ProxyExchangeArgumentResolver.java     | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/spring-cloud-gateway-mvc/src/main/java/org/springframework/cloud/gateway/mvc/config/ProxyExchangeArgumentResolver.java b/spring-cloud-gateway-mvc/src/main/java/org/springframework/cloud/gateway/mvc/config/ProxyExchangeArgumentResolver.java
index 009dc8de..f07987ac 100644
--- a/spring-cloud-gateway-mvc/src/main/java/org/springframework/cloud/gateway/mvc/config/ProxyExchangeArgumentResolver.java
+++ b/spring-cloud-gateway-mvc/src/main/java/org/springframework/cloud/gateway/mvc/config/ProxyExchangeArgumentResolver.java
@@ -58,8 +58,8 @@ public class ProxyExchangeArgumentResolver implements HandlerMethodArgumentResol
 	}
 
 	public void setAutoForwardedHeaders(Set<String> autoForwardedHeaders) {
-		this.autoForwardedHeaders = autoForwardedHeaders.stream().map(String::toLowerCase)
-				.collect(toSet());
+		this.autoForwardedHeaders = autoForwardedHeaders == null ? null
+				: autoForwardedHeaders.stream().map(String::toLowerCase).collect(toSet());
 	}
 
 	public void setSensitive(Set<String> sensitive) {