From 7b206458fe73b91ef320899697a576e6b0c994fc Mon Sep 17 00:00:00 2001
From: kezhenxu94 <kezhenxu94@apache.org>
Date: Mon, 23 Aug 2021 13:18:21 +0800
Subject: [PATCH] Fix NPE when OAP nodes synchronize events with each other in
 cluster mode (#7531)

---
 CHANGES.md                                                     | 1 +
 .../org/apache/skywalking/oap/server/core/source/Event.java    | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/CHANGES.md b/CHANGES.md
index ee1ed2376..dbe24b893 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -44,6 +44,7 @@ Release Notes.
 * Add a new API to test log analysis language.
 * Harden the security of Groovy-based DSL, MAL and LAL.
 * Fix distinct in Service/Instance/Endpoint query is not working.
+* Fix NPE when OAP nodes synchronize events with each other in cluster mode.
 
 #### UI
 
diff --git a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/source/Event.java b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/source/Event.java
index f985d0834..52f5b9f1c 100644
--- a/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/source/Event.java
+++ b/oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/source/Event.java
@@ -18,6 +18,7 @@
 
 package org.apache.skywalking.oap.server.core.source;
 
+import com.google.common.base.Strings;
 import java.util.HashMap;
 import java.util.Map;
 import lombok.EqualsAndHashCode;
@@ -186,7 +187,7 @@ public class Event extends Metrics implements ISource, WithMetadata, LongValueHo
         builder.addDataStrings(getName());
         builder.addDataStrings(getType());
         builder.addDataStrings(getMessage());
-        builder.addDataStrings(getParameters());
+        builder.addDataStrings(Strings.nullToEmpty(getParameters()));
 
         builder.addDataLongs(getStartTime());
         builder.addDataLongs(getEndTime());