From b7797f9e8d9cc96c6867c214279c0a789ba3cf26 Mon Sep 17 00:00:00 2001
From: Alexander Dinauer <alexander.dinauer@sentry.io>
Date: Wed, 3 Aug 2022 08:34:26 +0200
Subject: [PATCH 1/2] Prevent NPE by checking SentryTracer.timer for null again
 inside synchronized

---
 sentry/src/main/java/io/sentry/SentryTracer.java | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/sentry/src/main/java/io/sentry/SentryTracer.java b/sentry/src/main/java/io/sentry/SentryTracer.java
index a05d37c579..151766e53d 100644
--- a/sentry/src/main/java/io/sentry/SentryTracer.java
+++ b/sentry/src/main/java/io/sentry/SentryTracer.java
@@ -64,8 +64,8 @@ public final class SentryTracer implements ITransaction {
    */
   private final @Nullable Long idleTimeout;
 
-  private @Nullable TimerTask timerTask;
-  private @Nullable Timer timer = null;
+  private volatile @Nullable TimerTask timerTask;
+  private volatile @Nullable Timer timer = null;
   private final @NotNull Object timerLock = new Object();
   private final @NotNull SpanByTimestampComparator spanByTimestampComparator =
       new SpanByTimestampComparator();
@@ -344,8 +344,10 @@ public void finish(@Nullable SpanStatus status) {
 
       if (timer != null) {
         synchronized (timerLock) {
-          timer.cancel();
-          timer = null;
+          if (timer != null) {
+            timer.cancel();
+            timer = null;
+          }
         }
       }
 

From 7cab097b900155a395488777baf50909322af4ce Mon Sep 17 00:00:00 2001
From: Alexander Dinauer <alexander.dinauer@sentry.io>
Date: Wed, 3 Aug 2022 08:43:19 +0200
Subject: [PATCH 2/2] Add changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d4a71b56bc..a2f77a36bc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 ### Fixes
 
+- Prevent NPE by checking SentryTracer.timer for null again inside synchronized ([#2200](https://github.com/getsentry/sentry-java/pull/2200))
 - `attach-screenshot` set on Manual init. didn't work ([#2186](https://github.com/getsentry/sentry-java/pull/2186))
 - Remove extra space from `spring.factories` causing issues in old versions of Spring Boot ([#2181](https://github.com/getsentry/sentry-java/pull/2181))