[Java] Avoid failure of serializing a user-defined unserializable exception. (#13119)

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

@@ -0,0 +1,49 @@
+package io.ray.test;
+
+import io.ray.api.ActorHandle;
+import io.ray.api.Ray;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+public class TaskExceptionTest extends BaseTest {
+
+  private static class UnserializableClass {}
+
+  private static class UnserializableException extends RuntimeException {
+
+    public UnserializableException() {
+      super();
+    }
+
+    private UnserializableClass unSerializableClass = new UnserializableClass();
+  }
+
+  private static class MyActor {
+
+    public String sayHi() {
+      return "Hi";
+    }
+
+    public String throwUnserializableException() {
+      throw new UnserializableException();
+    }
+  }
+
+  private static String throwUnserializableException() {
+    throw new UnserializableException();
+  }
+
+  @Test
+  public void testThrowUnserializableExceptionInNormalTask() {
+    // Test that if a task throws an unserializable exception, the worker won't crash.
+    Assert.assertThrows(
+        (() -> Ray.task(TaskExceptionTest::throwUnserializableException).remote().get()));
+  }
+
+  @Test
+  public void testThrowUnserializableExceptionInActorTask() {
+    ActorHandle<MyActor> myActor = Ray.actor(MyActor::new).remote();
+    Assert.assertEquals("Hi", myActor.task(MyActor::sayHi).remote().get());
+    Assert.assertThrows((() -> myActor.task(MyActor::throwUnserializableException).remote().get()));
+  }
+}