[Java] fix actor restart failure when multi-worker is turned on (#13793)

java/test/src/main/java/io/ray/test/ActorRestartTest.java

@@ -3,15 +3,14 @@ package io.ray.test;
 import io.ray.api.ActorHandle;
 import io.ray.api.Ray;
 import io.ray.runtime.exception.RayActorException;
+import io.ray.runtime.exception.RayException;
 import io.ray.runtime.util.SystemUtil;
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import org.testng.Assert;
 import org.testng.annotations.Test;
 
-@Test(
-    groups = {"cluster"},
-    enabled = false)
+@Test(groups = {"cluster"})
 public class ActorRestartTest extends BaseTest {
 
   public static class Counter {
@@ -58,6 +57,7 @@ public class ActorRestartTest extends BaseTest {
     // Kill the actor process.
     killActorProcess(actor);
 
+    waitForActorAlive(actor);
     int value = actor.task(Counter::increase).remote().get();
     Assert.assertEquals(value, 1);
 
@@ -83,4 +83,18 @@ public class ActorRestartTest extends BaseTest {
     // Wait for the actor to be killed.
     TimeUnit.SECONDS.sleep(1);
   }
+
+  private static void waitForActorAlive(ActorHandle<Counter> actor) {
+    Assert.assertTrue(
+        TestUtils.waitForCondition(
+            () -> {
+              try {
+                actor.task(Counter::getPid).remote().get();
+                return true;
+              } catch (RayException e) {
+                return false;
+              }
+            },
+            10000));
+  }
 }