From a480346ee048d8f5c6634a7868460e1940a95f24 Mon Sep 17 00:00:00 2001
From: Lulu Wu <luluwu@fb.com>
Date: Mon, 26 Jul 2021 03:31:51 -0700
Subject: [PATCH] Make initializeMessageQueueThreads() thread safe

Summary:
**Context:**
Issue:
```java.lang.IllegalStateException: Message queue threads already initialized
	at com.facebook.react.bridge.ReactContext.initializeMessageQueueThreads(ReactContext.java:100)
```

Possible root cause:
1, ReactContext.initializeMessageQueueThreads() can be called from different threads, so it's not thread safe
2, ReactContext.initializeMessageQueueThreads() is called again without detroying the threads.

**Fix:**
Make initializeMessageQueueThreads() thread safe. If this won't fix T93983690, I'll continue investigating with possible root cause 2.

Changelog:
[Android][Changed] - Make initializeMessageQueueThreads() thread safe

Reviewed By: GijsWeterings

Differential Revision: D29877386

fbshipit-source-id: 11b32c7184e9e8d6f882474fd607538df12276b7
---
 .../main/java/com/facebook/react/bridge/ReactContext.java  | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/bridge/ReactContext.java b/ReactAndroid/src/main/java/com/facebook/react/bridge/ReactContext.java
index 9caaeff3508..b0763692435 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/bridge/ReactContext.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/bridge/ReactContext.java
@@ -89,11 +89,8 @@ public class ReactContext extends ContextWrapper {
     initializeMessageQueueThreads(queueConfig);
   }
 
-  /**
-   * Initialize message queue threads using a ReactQueueConfiguration. TODO (janzer) T43898341 Make
-   * this package instead of public
-   */
-  public void initializeMessageQueueThreads(ReactQueueConfiguration queueConfig) {
+  /** Initialize message queue threads using a ReactQueueConfiguration. */
+  public synchronized void initializeMessageQueueThreads(ReactQueueConfiguration queueConfig) {
     if (mUiMessageQueueThread != null
         || mNativeModulesMessageQueueThread != null
         || mJSMessageQueueThread != null) {