From 320047e1816f85786403e1399bccd68b536e44c3 Mon Sep 17 00:00:00 2001
From: Mattie Fu <mattiefu@google.com>
Date: Fri, 16 Jan 2026 14:40:02 -0500
Subject: [PATCH 1/2] test: fix race in emulator controller

---
 .../bigtable/emulator/core/EmulatorController.java   | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/google-cloud-bigtable-emulator-core/src/main/java/com/google/cloud/bigtable/emulator/core/EmulatorController.java b/google-cloud-bigtable-emulator-core/src/main/java/com/google/cloud/bigtable/emulator/core/EmulatorController.java
index 5ae045c8f7..4f3309f1b5 100644
--- a/google-cloud-bigtable-emulator-core/src/main/java/com/google/cloud/bigtable/emulator/core/EmulatorController.java
+++ b/google-cloud-bigtable-emulator-core/src/main/java/com/google/cloud/bigtable/emulator/core/EmulatorController.java
@@ -43,8 +43,8 @@ public class EmulatorController {
   private static final Logger LOGGER = Logger.getLogger(EmulatorController.class.getName());
 
   private final Path executable;
-  private Process process;
-  private boolean isStopped = true;
+  private volatile Process process;
+  private volatile boolean isStopped = true;
   private Thread shutdownHook;
 
   private int port;
@@ -134,9 +134,11 @@ public synchronized void start(int port)
     shutdownHook =
         new Thread(
             () -> {
-              if (!isStopped) {
-                isStopped = true;
-                process.destroy();
+              synchronized (EmulatorController.this) {
+                if (!isStopped) {
+                  isStopped = true;
+                  process.destroy();
+                }
               }
             });
 

From f7306e90fe281a347132aab7352ee85419766faf Mon Sep 17 00:00:00 2001
From: Mattie Fu <mattiefu@google.com>
Date: Fri, 16 Jan 2026 18:43:27 -0500
Subject: [PATCH 2/2] fix

---
 .../cloud/bigtable/emulator/core/EmulatorController.java    | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/google-cloud-bigtable-emulator-core/src/main/java/com/google/cloud/bigtable/emulator/core/EmulatorController.java b/google-cloud-bigtable-emulator-core/src/main/java/com/google/cloud/bigtable/emulator/core/EmulatorController.java
index 4f3309f1b5..d39c263faf 100644
--- a/google-cloud-bigtable-emulator-core/src/main/java/com/google/cloud/bigtable/emulator/core/EmulatorController.java
+++ b/google-cloud-bigtable-emulator-core/src/main/java/com/google/cloud/bigtable/emulator/core/EmulatorController.java
@@ -43,8 +43,8 @@ public class EmulatorController {
   private static final Logger LOGGER = Logger.getLogger(EmulatorController.class.getName());
 
   private final Path executable;
-  private volatile Process process;
-  private volatile boolean isStopped = true;
+  private Process process;
+  private boolean isStopped = true;
   private Thread shutdownHook;
 
   private int port;
@@ -137,9 +137,9 @@ public synchronized void start(int port)
               synchronized (EmulatorController.this) {
                 if (!isStopped) {
                   isStopped = true;
-                  process.destroy();
                 }
               }
+              process.destroy();
             });
 
     Runtime.getRuntime().addShutdownHook(shutdownHook);