From a2e5102657a8abe03812f0b025f457ca3d994921 Mon Sep 17 00:00:00 2001
From: tswstarplanet <tswstarplanet@apache.org>
Date: Mon, 13 Jul 2020 16:22:42 +0800
Subject: [PATCH] Fix NPE when unexport Metadata Service (#6450)

---
 .../apache/dubbo/config/bootstrap/DubboBootstrap.java    | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/dubbo-config/dubbo-config-api/src/main/java/org/apache/dubbo/config/bootstrap/DubboBootstrap.java b/dubbo-config/dubbo-config-api/src/main/java/org/apache/dubbo/config/bootstrap/DubboBootstrap.java
index 4af2dbcee6d..69859802422 100644
--- a/dubbo-config/dubbo-config-api/src/main/java/org/apache/dubbo/config/bootstrap/DubboBootstrap.java
+++ b/dubbo-config/dubbo-config-api/src/main/java/org/apache/dubbo/config/bootstrap/DubboBootstrap.java
@@ -74,6 +74,7 @@
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 import java.util.SortedSet;
 import java.util.concurrent.CompletableFuture;
@@ -1005,10 +1006,10 @@ private void exportMetadataService() {
     }
 
     private void unexportMetadataService() {
-        metadataServiceExporters
-                .stream()
-                .filter(this::supports)
-                .forEach(MetadataServiceExporter::unexport);
+        Optional.ofNullable(metadataServiceExporters)
+                .ifPresent(set -> set.stream()
+                        .filter(this::supports)
+                        .forEach(MetadataServiceExporter::unexport));
     }
 
     private boolean supports(MetadataServiceExporter exporter) {