[Java] Support exchange ObjectRef between processes (#10729)

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

@@ -0,0 +1,45 @@
+package io.ray.test;
+
+import io.ray.api.ActorHandle;
+import io.ray.api.ObjectRef;
+import io.ray.api.Ray;
+import java.util.ArrayList;
+import java.util.List;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+public class ObjectRefTransferTest extends BaseTest {
+
+  @Test
+  public void testObjectTransfer() {
+    ObjectRef<String> objectRef = Ray.put("test");
+    List<ObjectRef<String>> data = new ArrayList<>();
+    data.add(objectRef);
+
+    ActorHandle<RemoteActor> handle = Ray.actor(RemoteActor::new).remote();
+    String result = handle.task(RemoteActor::get, data).remote().get();
+    Assert.assertEquals(result, "test");
+  }
+
+  @Test
+  public void testNestedObjectId() {
+    ObjectRef<String> inner = Ray.put("inner");
+    ObjectRef<ObjectRef<String>> outer = Ray.put(inner);
+    List<ObjectRef<ObjectRef<String>>> data = new ArrayList<>();
+    data.add(outer);
+
+    ActorHandle<RemoteActor> handle = Ray.actor(RemoteActor::new).remote();
+    String result = handle.task(RemoteActor::getNested, data).remote().get();
+    Assert.assertEquals(result, "inner");
+  }
+
+  public static class RemoteActor {
+    public String get(List<ObjectRef<String>> value) {
+      return Ray.get(value.get(0));
+    }
+
+    public String getNested(List<ObjectRef<ObjectRef<String>>> value) {
+      return Ray.get(value.get(0).get());
+    }
+  }
+}