refactor(tests): simplify TimerShutdownHook body and drop Supplier indirection

Per PR #99 review feedback: Timer.stop() already cancels all pending
tasks (per Netty 4.2 javadoc), so the explicit pending.forEach(cancel)
pass in the shutdown hook body is dead work. After stop() returns the
worker thread is dead, so cancel() on the returned handles is a no-op,
and stop() never returns null. Also drop the Supplier<Timer> wrapper at
every call site — the timer reference is a static field, stable for the
JVM lifetime.

Body collapses to one line per module:
  Runtime.getRuntime().addShutdownHook(new Thread(timer::stop, name));

Net diff: -56 LOC across 8 files. box-integration profile passes
(Tarantool 2.11.8).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: dkasimovskiy

tarantool-client/src/test/java/io/tarantool/client/integration/TarantoolCrudClientWithRetryTest.java

@@ -100,8 +100,7 @@ private void execute() {
   private static final Timer timerService = new HashedWheelTimer();
 
   static {
-    TimerShutdownHook.register(
-        () -> timerService, "tarantool-crud-client-retry-test-timer-shutdown");
+    TimerShutdownHook.register(timerService, "tarantool-crud-client-retry-test-timer-shutdown");
   }
 
   @BeforeAll

tarantool-client/src/test/java/io/tarantool/client/integration/TimerShutdownHook.java

@@ -5,26 +5,12 @@
 
 package io.tarantool.client.integration;
 
-import java.util.Set;
-import java.util.function.Supplier;
-
-import io.netty.util.Timeout;
 import io.netty.util.Timer;
 
 public final class TimerShutdownHook {
   private TimerShutdownHook() {}
 
-  public static void register(Supplier<Timer> timerRef, String name) {
-    Runtime.getRuntime()
-        .addShutdownHook(
-            new Thread(
-                () -> {
-                  Timer t = timerRef.get();
-                  if (t != null) {
-                    Set<Timeout> pending = t.stop();
-                    if (pending != null) pending.forEach(Timeout::cancel);
-                  }
-                },
-                name));
+  public static void register(Timer timer, String name) {
+    Runtime.getRuntime().addShutdownHook(new Thread(timer::stop, name));
   }
 }

tarantool-core/src/test/java/io/tarantool/core/integration/BaseTest.java

@@ -63,7 +63,7 @@ public abstract class BaseTest {
   protected static ConnectionFactory factory = new ConnectionFactory(bootstrap, timerService);
 
   static {
-    TimerShutdownHook.register(() -> timerService, "base-test-timer-shutdown");
+    TimerShutdownHook.register(timerService, "base-test-timer-shutdown");
   }
 
   protected static ArrayValue decodeTuple(IProtoClient client, ArrayValue arrayValue)

tarantool-core/src/test/java/io/tarantool/core/integration/TimerShutdownHook.java

@@ -5,26 +5,12 @@
 
 package io.tarantool.core.integration;
 
-import java.util.Set;
-import java.util.function.Supplier;
-
-import io.netty.util.Timeout;
 import io.netty.util.Timer;
 
 public final class TimerShutdownHook {
   private TimerShutdownHook() {}
 
-  public static void register(Supplier<Timer> timerRef, String name) {
-    Runtime.getRuntime()
-        .addShutdownHook(
-            new Thread(
-                () -> {
-                  Timer t = timerRef.get();
-                  if (t != null) {
-                    Set<Timeout> pending = t.stop();
-                    if (pending != null) pending.forEach(Timeout::cancel);
-                  }
-                },
-                name));
+  public static void register(Timer timer, String name) {
+    Runtime.getRuntime().addShutdownHook(new Thread(timer::stop, name));
   }
 }

tarantool-jackson-mapping/src/test/java/io/tarantool/mapping/integration/BaseTest.java

@@ -49,6 +49,6 @@ public abstract class BaseTest {
   protected static final ConnectionFactory factory = new ConnectionFactory(bootstrap, timerService);
 
   static {
-    TimerShutdownHook.register(() -> timerService, "jackson-mapping-base-test-timer-shutdown");
+    TimerShutdownHook.register(timerService, "jackson-mapping-base-test-timer-shutdown");
   }
 }

tarantool-jackson-mapping/src/test/java/io/tarantool/mapping/integration/TimerShutdownHook.java

@@ -5,26 +5,12 @@
 
 package io.tarantool.mapping.integration;
 
-import java.util.Set;
-import java.util.function.Supplier;
-
-import io.netty.util.Timeout;
 import io.netty.util.Timer;
 
 public final class TimerShutdownHook {
   private TimerShutdownHook() {}
 
-  public static void register(Supplier<Timer> timerRef, String name) {
-    Runtime.getRuntime()
-        .addShutdownHook(
-            new Thread(
-                () -> {
-                  Timer t = timerRef.get();
-                  if (t != null) {
-                    Set<Timeout> pending = t.stop();
-                    if (pending != null) pending.forEach(Timeout::cancel);
-                  }
-                },
-                name));
+  public static void register(Timer timer, String name) {
+    Runtime.getRuntime().addShutdownHook(new Thread(timer::stop, name));
   }
 }

tarantool-schema/src/test/java/io/tarantool/client/integration/TarantoolSchemaFetcherTest.java

@@ -76,7 +76,7 @@ public class TarantoolSchemaFetcherTest {
   private static final ConnectionFactory factory = new ConnectionFactory(bootstrap, timerService);
 
   static {
-    TimerShutdownHook.register(() -> timerService, "tarantool-schema-fetcher-test-timer-shutdown");
+    TimerShutdownHook.register(timerService, "tarantool-schema-fetcher-test-timer-shutdown");
   }
 
   private static TarantoolContainer<?> tt;

tarantool-schema/src/test/java/io/tarantool/client/integration/TimerShutdownHook.java

@@ -5,26 +5,12 @@
 
 package io.tarantool.client.integration;
 
-import java.util.Set;
-import java.util.function.Supplier;
-
-import io.netty.util.Timeout;
 import io.netty.util.Timer;
 
 public final class TimerShutdownHook {
   private TimerShutdownHook() {}
 
-  public static void register(Supplier<Timer> timerRef, String name) {
-    Runtime.getRuntime()
-        .addShutdownHook(
-            new Thread(
-                () -> {
-                  Timer t = timerRef.get();
-                  if (t != null) {
-                    Set<Timeout> pending = t.stop();
-                    if (pending != null) pending.forEach(Timeout::cancel);
-                  }
-                },
-                name));
+  public static void register(Timer timer, String name) {
+    Runtime.getRuntime().addShutdownHook(new Thread(timer::stop, name));
   }
 }