diff --git a/src/ray/core_worker/common.h b/src/ray/core_worker/common.h
index 750712760..ee20e88f4 100644
--- a/src/ray/core_worker/common.h
+++ b/src/ray/core_worker/common.h
@@ -5,7 +5,7 @@
 
 #include "ray/common/buffer.h"
 #include "ray/common/id.h"
-#include "ray/protobuf/gcs.pb.h"
+#include "ray/gcs/format/gcs_generated.h"
 #include "ray/raylet/raylet_client.h"
 #include "ray/raylet/task_spec.h"
 
@@ -17,7 +17,7 @@ enum class WorkerType { WORKER, DRIVER };
 /// Information about a remote function.
 struct RayFunction {
   /// Language of the remote function.
-  const ray::rpc::Language language;
+  const Language language;
   /// Function descriptor of the remote function.
   const std::vector<std::string> function_descriptor;
 };
@@ -107,48 +107,6 @@ enum class StoreProviderType { PLASMA };
 
 enum class TaskTransportType { RAYLET };
 
-/// Translate from ray::rpc::Language to Language type (required by raylet client).
-///
-/// \param[in] language Language for a task.
-/// \return Translated task language.
-inline ::Language ToRayletTaskLanguage(ray::rpc::Language language) {
-  switch (language) {
-  case ray::rpc::Language::JAVA:
-    return ::Language::JAVA;
-    break;
-  case ray::rpc::Language::PYTHON:
-    return ::Language::PYTHON;
-    break;
-  case ray::rpc::Language::CPP:
-    return ::Language::CPP;
-    break;
-  default:
-    RAY_LOG(FATAL) << "Invalid language specified: " << static_cast<int>(language);
-    break;
-  }
-}
-
-/// Translate from Language to ray::rpc::Language type (required by core worker).
-///
-/// \param[in] language Language for a task.
-/// \return Translated task language.
-inline ray::rpc::Language ToRpcTaskLanguage(::Language language) {
-  switch (language) {
-  case Language::JAVA:
-    return ray::rpc::Language::JAVA;
-    break;
-  case Language::PYTHON:
-    return ray::rpc::Language::PYTHON;
-    break;
-  case Language::CPP:
-    return ray::rpc::Language::CPP;
-    break;
-  default:
-    RAY_LOG(FATAL) << "Invalid language specified: " << static_cast<int>(language);
-    break;
-  }
-}
-
 }  // namespace ray
 
 #endif  // RAY_CORE_WORKER_COMMON_H
diff --git a/src/ray/core_worker/core_worker.cc b/src/ray/core_worker/core_worker.cc
index 03b20329c..57e35d4fd 100644
--- a/src/ray/core_worker/core_worker.cc
+++ b/src/ray/core_worker/core_worker.cc
@@ -3,31 +3,22 @@
 
 namespace ray {
 
-CoreWorker::CoreWorker(const enum WorkerType worker_type,
-                       const ray::rpc::Language language, const std::string &store_socket,
-                       const std::string &raylet_socket, const JobID &job_id)
+CoreWorker::CoreWorker(const enum WorkerType worker_type, const ::Language language,
+                       const std::string &store_socket, const std::string &raylet_socket,
+                       const JobID &job_id)
     : worker_type_(worker_type),
       language_(language),
-      store_socket_(store_socket),
       raylet_socket_(raylet_socket),
       worker_context_(worker_type, job_id),
+      // TODO(zhijunfu): currently RayletClient would crash in its constructor
+      // if it cannot connect to Raylet after a number of retries, this needs
+      // to be changed so that the worker (java/python .etc) can retrieve and
+      // handle the error instead of crashing.
       raylet_client_(raylet_socket_,
                      ClientID::FromBinary(worker_context_.GetWorkerID().Binary()),
                      (worker_type_ == ray::WorkerType::WORKER),
-                     worker_context_.GetCurrentJobID(), ToRayletTaskLanguage(language_)),
-      task_interface_(*this),
-      object_interface_(*this),
-      task_execution_interface_(*this) {
-  // TODO(zhijunfu): currently RayletClient would crash in its constructor if it cannot
-  // connect to Raylet after a number of retries, this needs to be changed
-  // so that the worker (java/python .etc) can retrieve and handle the error
-  // instead of crashing.
-  auto status = store_client_.Connect(store_socket_);
-  if (!status.ok()) {
-    RAY_LOG(ERROR) << "Connecting plasma store failed when trying to construct"
-                   << " core worker: " << status.message();
-    throw std::runtime_error(status.message());
-  }
-}
-
+                     worker_context_.GetCurrentJobID(), language_),
+      task_interface_(worker_context_, raylet_client_),
+      object_interface_(worker_context_, raylet_client_, store_socket),
+      task_execution_interface_(worker_context_, raylet_client_, object_interface_) {}
 }  // namespace ray
diff --git a/src/ray/core_worker/core_worker.h b/src/ray/core_worker/core_worker.h
index 7abaf46b9..3f567f0af 100644
--- a/src/ray/core_worker/core_worker.h
+++ b/src/ray/core_worker/core_worker.h
@@ -7,6 +7,7 @@
 #include "ray/core_worker/object_interface.h"
 #include "ray/core_worker/task_execution.h"
 #include "ray/core_worker/task_interface.h"
+#include "ray/gcs/format/gcs_generated.h"
 #include "ray/raylet/raylet_client.h"
 
 namespace ray {
@@ -22,7 +23,7 @@ class CoreWorker {
   /// \param[in] langauge Language of this worker.
   ///
   /// NOTE(zhijunfu): the constructor would throw if a failure happens.
-  CoreWorker(const WorkerType worker_type, const ray::rpc::Language language,
+  CoreWorker(const WorkerType worker_type, const ::Language language,
              const std::string &store_socket, const std::string &raylet_socket,
              const JobID &job_id = JobID::Nil());
 
@@ -30,7 +31,7 @@ class CoreWorker {
   enum WorkerType WorkerType() const { return worker_type_; }
 
   /// Language of this worker.
-  ray::rpc::Language Language() const { return language_; }
+  ::Language Language() const { return language_; }
 
   /// Return the `CoreWorkerTaskInterface` that contains the methods related to task
   /// submisson.
@@ -49,10 +50,7 @@ class CoreWorker {
   const enum WorkerType worker_type_;
 
   /// Language of this worker.
-  const ray::rpc::Language language_;
-
-  /// Plasma store socket name.
-  const std::string store_socket_;
+  const ::Language language_;
 
   /// raylet socket name.
   const std::string raylet_socket_;
@@ -60,12 +58,6 @@ class CoreWorker {
   /// Worker context.
   WorkerContext worker_context_;
 
-  /// Plasma store client.
-  plasma::PlasmaClient store_client_;
-
-  /// Mutex to protect store_client_.
-  std::mutex store_client_mutex_;
-
   /// Raylet client.
   RayletClient raylet_client_;
 
@@ -77,10 +69,6 @@ class CoreWorker {
 
   /// The `CoreWorkerTaskExecutionInterface` instance.
   CoreWorkerTaskExecutionInterface task_execution_interface_;
-
-  friend class CoreWorkerTaskInterface;
-  friend class CoreWorkerObjectInterface;
-  friend class CoreWorkerTaskExecutionInterface;
 };
 
 }  // namespace ray
diff --git a/src/ray/core_worker/core_worker_test.cc b/src/ray/core_worker/core_worker_test.cc
index 46bc10dc6..cf40e175f 100644
--- a/src/ray/core_worker/core_worker_test.cc
+++ b/src/ray/core_worker/core_worker_test.cc
@@ -124,9 +124,8 @@ class CoreWorkerTest : public ::testing::Test {
   void TearDown() {}
 
   void TestNormalTask(const std::unordered_map<std::string, double> &resources) {
-    CoreWorker driver(WorkerType::DRIVER, ray::rpc::Language::PYTHON,
-                      raylet_store_socket_names_[0], raylet_socket_names_[0],
-                      JobID::FromRandom());
+    CoreWorker driver(WorkerType::DRIVER, Language::PYTHON, raylet_store_socket_names_[0],
+                      raylet_socket_names_[0], JobID::FromRandom());
 
     // Test pass by value.
     {
@@ -134,7 +133,7 @@ class CoreWorkerTest : public ::testing::Test {
 
       auto buffer1 = std::make_shared<LocalMemoryBuffer>(array1, sizeof(array1));
 
-      RayFunction func{ray::rpc::Language::PYTHON, {}};
+      RayFunction func{Language::PYTHON, {}};
       std::vector<TaskArg> args;
       args.emplace_back(TaskArg::PassByValue(buffer1));
 
@@ -165,7 +164,7 @@ class CoreWorkerTest : public ::testing::Test {
       std::vector<TaskArg> args;
       args.emplace_back(TaskArg::PassByReference(object_id));
 
-      RayFunction func{ray::rpc::Language::PYTHON, {}};
+      RayFunction func{Language::PYTHON, {}};
       TaskOptions options;
 
       std::vector<ObjectID> return_ids;
@@ -184,9 +183,8 @@ class CoreWorkerTest : public ::testing::Test {
   }
 
   void TestActorTask(const std::unordered_map<std::string, double> &resources) {
-    CoreWorker driver(WorkerType::DRIVER, ray::rpc::Language::PYTHON,
-                      raylet_store_socket_names_[0], raylet_socket_names_[0],
-                      JobID::FromRandom());
+    CoreWorker driver(WorkerType::DRIVER, Language::PYTHON, raylet_store_socket_names_[0],
+                      raylet_socket_names_[0], JobID::FromRandom());
 
     std::unique_ptr<ActorHandle> actor_handle;
 
@@ -195,7 +193,7 @@ class CoreWorkerTest : public ::testing::Test {
       uint8_t array[] = {1, 2, 3};
       auto buffer = std::make_shared<LocalMemoryBuffer>(array, sizeof(array));
 
-      RayFunction func{ray::rpc::Language::PYTHON, {}};
+      RayFunction func{Language::PYTHON, {}};
       std::vector<TaskArg> args;
       args.emplace_back(TaskArg::PassByValue(buffer));
 
@@ -223,7 +221,7 @@ class CoreWorkerTest : public ::testing::Test {
 
       TaskOptions options{1, resources};
       std::vector<ObjectID> return_ids;
-      RayFunction func{ray::rpc::Language::PYTHON, {}};
+      RayFunction func{Language::PYTHON, {}};
       RAY_CHECK_OK(driver.Tasks().SubmitActorTask(*actor_handle, func, args, options,
                                                   &return_ids));
       RAY_CHECK(return_ids.size() == 1);
@@ -304,7 +302,7 @@ TEST_F(ZeroNodeTest, TestWorkerContext) {
 
 TEST_F(ZeroNodeTest, TestActorHandle) {
   ActorHandle handle1(ActorID::FromRandom(), ActorHandleID::FromRandom(),
-                      ray::rpc::Language::JAVA,
+                      ::Language::JAVA,
                       {"org.ray.exampleClass", "exampleMethod", "exampleSignature"});
 
   auto forkedHandle1 = handle1.Fork();
@@ -336,7 +334,7 @@ TEST_F(ZeroNodeTest, TestActorHandle) {
 }
 
 TEST_F(SingleNodeTest, TestObjectInterface) {
-  CoreWorker core_worker(WorkerType::DRIVER, ray::rpc::Language::PYTHON,
+  CoreWorker core_worker(WorkerType::DRIVER, Language::PYTHON,
                          raylet_store_socket_names_[0], raylet_socket_names_[0],
                          JobID::FromRandom());
 
@@ -400,13 +398,11 @@ TEST_F(SingleNodeTest, TestObjectInterface) {
 }
 
 TEST_F(TwoNodeTest, TestObjectInterfaceCrossNodes) {
-  CoreWorker worker1(WorkerType::DRIVER, ray::rpc::Language::PYTHON,
-                     raylet_store_socket_names_[0], raylet_socket_names_[0],
-                     JobID::FromRandom());
+  CoreWorker worker1(WorkerType::DRIVER, Language::PYTHON, raylet_store_socket_names_[0],
+                     raylet_socket_names_[0], JobID::FromRandom());
 
-  CoreWorker worker2(WorkerType::DRIVER, ray::rpc::Language::PYTHON,
-                     raylet_store_socket_names_[1], raylet_socket_names_[1],
-                     JobID::FromRandom());
+  CoreWorker worker2(WorkerType::DRIVER, Language::PYTHON, raylet_store_socket_names_[1],
+                     raylet_socket_names_[1], JobID::FromRandom());
 
   uint8_t array1[] = {1, 2, 3, 4, 5, 6, 7, 8};
   uint8_t array2[] = {10, 11, 12, 13, 14, 15};
@@ -491,7 +487,7 @@ TEST_F(TwoNodeTest, TestActorTaskCrossNodes) {
 
 TEST_F(SingleNodeTest, TestCoreWorkerConstructorFailure) {
   try {
-    CoreWorker core_worker(WorkerType::DRIVER, ray::rpc::Language::PYTHON, "",
+    CoreWorker core_worker(WorkerType::DRIVER, Language::PYTHON, "",
                            raylet_socket_names_[0], JobID::FromRandom());
   } catch (const std::exception &e) {
     std::cout << "Caught exception when constructing core worker: " << e.what();
diff --git a/src/ray/core_worker/mock_worker.cc b/src/ray/core_worker/mock_worker.cc
index 62917cb94..5097f6bd5 100644
--- a/src/ray/core_worker/mock_worker.cc
+++ b/src/ray/core_worker/mock_worker.cc
@@ -17,8 +17,8 @@ namespace ray {
 class MockWorker {
  public:
   MockWorker(const std::string &store_socket, const std::string &raylet_socket)
-      : worker_(WorkerType::WORKER, ray::rpc::Language::PYTHON, store_socket,
-                raylet_socket, JobID::FromRandom()) {}
+      : worker_(WorkerType::WORKER, Language::PYTHON, store_socket, raylet_socket,
+                JobID::FromRandom()) {}
 
   void Run() {
     auto executor_func = [this](const RayFunction &ray_function,
diff --git a/src/ray/core_worker/object_interface.cc b/src/ray/core_worker/object_interface.cc
index 4e3be942b..53836431f 100644
--- a/src/ray/core_worker/object_interface.cc
+++ b/src/ray/core_worker/object_interface.cc
@@ -1,23 +1,22 @@
 #include "ray/core_worker/object_interface.h"
 #include "ray/common/ray_config.h"
-#include "ray/core_worker/context.h"
-#include "ray/core_worker/core_worker.h"
 #include "ray/core_worker/store_provider/plasma_store_provider.h"
 
 namespace ray {
 
-CoreWorkerObjectInterface::CoreWorkerObjectInterface(CoreWorker &core_worker)
-    : core_worker_(core_worker) {
+CoreWorkerObjectInterface::CoreWorkerObjectInterface(WorkerContext &worker_context,
+                                                     RayletClient &raylet_client,
+                                                     const std::string &store_socket)
+    : worker_context_(worker_context), raylet_client_(raylet_client) {
   store_providers_.emplace(
       static_cast<int>(StoreProviderType::PLASMA),
-      std::unique_ptr<CoreWorkerStoreProvider>(new CoreWorkerPlasmaStoreProvider(
-          core_worker_.store_client_, core_worker_.store_client_mutex_,
-          core_worker_.raylet_client_)));
+      std::unique_ptr<CoreWorkerStoreProvider>(
+          new CoreWorkerPlasmaStoreProvider(store_socket, raylet_client_)));
 }
 
 Status CoreWorkerObjectInterface::Put(const RayObject &object, ObjectID *object_id) {
-  ObjectID put_id = ObjectID::ForPut(core_worker_.worker_context_.GetCurrentTaskID(),
-                                     core_worker_.worker_context_.GetNextPutIndex());
+  ObjectID put_id = ObjectID::ForPut(worker_context_.GetCurrentTaskID(),
+                                     worker_context_.GetNextPutIndex());
   *object_id = put_id;
   return Put(object, put_id);
 }
@@ -32,8 +31,8 @@ Status CoreWorkerObjectInterface::Get(const std::vector<ObjectID> &ids,
                                       int64_t timeout_ms,
                                       std::vector<std::shared_ptr<RayObject>> *results) {
   auto type = static_cast<int>(StoreProviderType::PLASMA);
-  return store_providers_[type]->Get(
-      ids, timeout_ms, core_worker_.worker_context_.GetCurrentTaskID(), results);
+  return store_providers_[type]->Get(ids, timeout_ms, worker_context_.GetCurrentTaskID(),
+                                     results);
 }
 
 Status CoreWorkerObjectInterface::Wait(const std::vector<ObjectID> &object_ids,
@@ -41,8 +40,7 @@ Status CoreWorkerObjectInterface::Wait(const std::vector<ObjectID> &object_ids,
                                        std::vector<bool> *results) {
   auto type = static_cast<int>(StoreProviderType::PLASMA);
   return store_providers_[type]->Wait(object_ids, num_objects, timeout_ms,
-                                      core_worker_.worker_context_.GetCurrentTaskID(),
-                                      results);
+                                      worker_context_.GetCurrentTaskID(), results);
 }
 
 Status CoreWorkerObjectInterface::Delete(const std::vector<ObjectID> &object_ids,
diff --git a/src/ray/core_worker/object_interface.h b/src/ray/core_worker/object_interface.h
index 218b155e8..7d3d42a2d 100644
--- a/src/ray/core_worker/object_interface.h
+++ b/src/ray/core_worker/object_interface.h
@@ -6,6 +6,7 @@
 #include "ray/common/id.h"
 #include "ray/common/status.h"
 #include "ray/core_worker/common.h"
+#include "ray/core_worker/context.h"
 #include "ray/core_worker/store_provider/store_provider.h"
 
 namespace ray {
@@ -16,7 +17,8 @@ class CoreWorkerStoreProvider;
 /// The interface that contains all `CoreWorker` methods that are related to object store.
 class CoreWorkerObjectInterface {
  public:
-  CoreWorkerObjectInterface(CoreWorker &core_worker);
+  CoreWorkerObjectInterface(WorkerContext &worker_context, RayletClient &raylet_client,
+                            const std::string &store_socket);
 
   /// Put an object into object store.
   ///
@@ -62,8 +64,10 @@ class CoreWorkerObjectInterface {
                 bool delete_creating_tasks);
 
  private:
-  /// Reference to the parent CoreWorker instance.
-  CoreWorker &core_worker_;
+  /// Reference to the parent CoreWorker's context.
+  WorkerContext &worker_context_;
+  /// Reference to the parent CoreWorker's raylet client.
+  RayletClient &raylet_client_;
 
   /// All the store providers supported.
   std::unordered_map<int, std::unique_ptr<CoreWorkerStoreProvider>> store_providers_;
diff --git a/src/ray/core_worker/store_provider/plasma_store_provider.cc b/src/ray/core_worker/store_provider/plasma_store_provider.cc
index 17ff2da91..652e64c02 100644
--- a/src/ray/core_worker/store_provider/plasma_store_provider.cc
+++ b/src/ray/core_worker/store_provider/plasma_store_provider.cc
@@ -7,11 +7,15 @@
 namespace ray {
 
 CoreWorkerPlasmaStoreProvider::CoreWorkerPlasmaStoreProvider(
-    plasma::PlasmaClient &store_client, std::mutex &store_client_mutex,
-    RayletClient &raylet_client)
-    : store_client_(store_client),
-      store_client_mutex_(store_client_mutex),
-      raylet_client_(raylet_client) {}
+    const std::string &store_socket, RayletClient &raylet_client)
+    : raylet_client_(raylet_client) {
+  auto status = store_client_.Connect(store_socket);
+  if (!status.ok()) {
+    RAY_LOG(ERROR) << "Connecting plasma store failed when trying to construct"
+                   << " core worker: " << status.message();
+    throw std::runtime_error(status.message());
+  }
+}
 
 Status CoreWorkerPlasmaStoreProvider::Put(const RayObject &object,
                                           const ObjectID &object_id) {
diff --git a/src/ray/core_worker/store_provider/plasma_store_provider.h b/src/ray/core_worker/store_provider/plasma_store_provider.h
index a82b96350..db9c39639 100644
--- a/src/ray/core_worker/store_provider/plasma_store_provider.h
+++ b/src/ray/core_worker/store_provider/plasma_store_provider.h
@@ -17,8 +17,7 @@ class CoreWorker;
 /// local and remote store, remote access is done via raylet.
 class CoreWorkerPlasmaStoreProvider : public CoreWorkerStoreProvider {
  public:
-  CoreWorkerPlasmaStoreProvider(plasma::PlasmaClient &store_client,
-                                std::mutex &store_client_mutex,
+  CoreWorkerPlasmaStoreProvider(const std::string &store_socket,
                                 RayletClient &raylet_client);
 
   /// Put an object with specified ID into object store.
@@ -62,10 +61,10 @@ class CoreWorkerPlasmaStoreProvider : public CoreWorkerStoreProvider {
 
  private:
   /// Plasma store client.
-  plasma::PlasmaClient &store_client_;
+  plasma::PlasmaClient store_client_;
 
   /// Mutex to protect store_client_.
-  std::mutex &store_client_mutex_;
+  std::mutex store_client_mutex_;
 
   /// Raylet client.
   RayletClient &raylet_client_;
diff --git a/src/ray/core_worker/task_execution.cc b/src/ray/core_worker/task_execution.cc
index 86093cefa..ce7c88986 100644
--- a/src/ray/core_worker/task_execution.cc
+++ b/src/ray/core_worker/task_execution.cc
@@ -6,12 +6,12 @@
 namespace ray {
 
 CoreWorkerTaskExecutionInterface::CoreWorkerTaskExecutionInterface(
-    CoreWorker &core_worker)
-    : core_worker_(core_worker) {
-  task_receivers.emplace(
-      static_cast<int>(TaskTransportType::RAYLET),
-      std::unique_ptr<CoreWorkerRayletTaskReceiver>(
-          new CoreWorkerRayletTaskReceiver(core_worker_.raylet_client_)));
+    WorkerContext &worker_context, RayletClient &raylet_client,
+    CoreWorkerObjectInterface &object_interface)
+    : worker_context_(worker_context), object_interface_(object_interface) {
+  task_receivers.emplace(static_cast<int>(TaskTransportType::RAYLET),
+                         std::unique_ptr<CoreWorkerRayletTaskReceiver>(
+                             new CoreWorkerRayletTaskReceiver(raylet_client)));
 }
 
 Status CoreWorkerTaskExecutionInterface::Run(const TaskExecutor &executor) {
@@ -27,10 +27,9 @@ Status CoreWorkerTaskExecutionInterface::Run(const TaskExecutor &executor) {
 
     for (const auto &task : tasks) {
       const auto &spec = task.GetTaskSpecification();
-      core_worker_.worker_context_.SetCurrentTask(spec);
+      worker_context_.SetCurrentTask(spec);
 
-      ray::rpc::Language language = ToRpcTaskLanguage(spec.GetLanguage());
-      RayFunction func{language, spec.FunctionDescriptor()};
+      RayFunction func{spec.GetLanguage(), spec.FunctionDescriptor()};
 
       std::vector<std::shared_ptr<RayObject>> args;
       RAY_CHECK_OK(BuildArgsForExecutor(spec, &args));
@@ -90,7 +89,7 @@ Status CoreWorkerTaskExecutionInterface::BuildArgsForExecutor(
   }
 
   std::vector<std::shared_ptr<RayObject>> results;
-  auto status = core_worker_.object_interface_.Get(object_ids_to_fetch, -1, &results);
+  auto status = object_interface_.Get(object_ids_to_fetch, -1, &results);
   if (status.ok()) {
     for (size_t i = 0; i < results.size(); i++) {
       (*args)[indices[i]] = results[i];
diff --git a/src/ray/core_worker/task_execution.h b/src/ray/core_worker/task_execution.h
index a59784691..22491aa03 100644
--- a/src/ray/core_worker/task_execution.h
+++ b/src/ray/core_worker/task_execution.h
@@ -4,7 +4,8 @@
 #include "ray/common/buffer.h"
 #include "ray/common/status.h"
 #include "ray/core_worker/common.h"
-#include "ray/core_worker/store_provider/store_provider.h"
+#include "ray/core_worker/context.h"
+#include "ray/core_worker/object_interface.h"
 #include "ray/core_worker/transport/transport.h"
 
 namespace ray {
@@ -19,7 +20,10 @@ class TaskSpecification;
 /// execution.
 class CoreWorkerTaskExecutionInterface {
  public:
-  CoreWorkerTaskExecutionInterface(CoreWorker &core_worker);
+  CoreWorkerTaskExecutionInterface(WorkerContext &worker_context,
+                                   RayletClient &raylet_client,
+                                   CoreWorkerObjectInterface &object_interface);
+
   /// The callback provided app-language workers that executes tasks.
   ///
   /// \param ray_function[in] Information about the function to execute.
@@ -46,8 +50,10 @@ class CoreWorkerTaskExecutionInterface {
   Status BuildArgsForExecutor(const raylet::TaskSpecification &spec,
                               std::vector<std::shared_ptr<RayObject>> *args);
 
-  /// Reference to the parent CoreWorker instance.
-  CoreWorker &core_worker_;
+  /// Reference to the parent CoreWorker's context.
+  WorkerContext &worker_context_;
+  /// Reference to the parent CoreWorker's objects interface.
+  CoreWorkerObjectInterface &object_interface_;
 
   /// All the task task receivers supported.
   std::unordered_map<int, std::unique_ptr<CoreWorkerTaskReceiver>> task_receivers;
diff --git a/src/ray/core_worker/task_interface.cc b/src/ray/core_worker/task_interface.cc
index 8f1e05b0d..c1510726d 100644
--- a/src/ray/core_worker/task_interface.cc
+++ b/src/ray/core_worker/task_interface.cc
@@ -8,7 +8,7 @@ namespace ray {
 
 ActorHandle::ActorHandle(
     const class ActorID &actor_id, const class ActorHandleID &actor_handle_id,
-    const ray::rpc::Language actor_language,
+    const ::Language actor_language,
     const std::vector<std::string> &actor_creation_task_function_descriptor) {
   inner_.set_actor_id(actor_id.Data(), actor_id.Size());
   inner_.set_actor_handle_id(actor_handle_id.Data(), actor_handle_id.Size());
@@ -30,8 +30,8 @@ ray::ActorHandleID ActorHandle::ActorHandleID() const {
   return ActorHandleID::FromBinary(inner_.actor_handle_id());
 };
 
-ray::rpc::Language ActorHandle::ActorLanguage() const {
-  return (ray::rpc::Language)inner_.actor_language();
+::Language ActorHandle::ActorLanguage() const {
+  return (::Language)inner_.actor_language();
 };
 
 std::vector<std::string> ActorHandle::ActorCreationTaskFunctionDescriptor() const {
@@ -92,19 +92,19 @@ std::vector<ray::ActorHandleID> ActorHandle::NewActorHandles() const {
 
 void ActorHandle::ClearNewActorHandles() { new_actor_handles_.clear(); }
 
-CoreWorkerTaskInterface::CoreWorkerTaskInterface(CoreWorker &core_worker)
-    : core_worker_(core_worker) {
-  task_submitters_.emplace(
-      static_cast<int>(TaskTransportType::RAYLET),
-      std::unique_ptr<CoreWorkerRayletTaskSubmitter>(
-          new CoreWorkerRayletTaskSubmitter(core_worker_.raylet_client_)));
+CoreWorkerTaskInterface::CoreWorkerTaskInterface(WorkerContext &worker_context,
+                                                 RayletClient &raylet_client)
+    : worker_context_(worker_context) {
+  task_submitters_.emplace(static_cast<int>(TaskTransportType::RAYLET),
+                           std::unique_ptr<CoreWorkerRayletTaskSubmitter>(
+                               new CoreWorkerRayletTaskSubmitter(raylet_client)));
 }
 
 Status CoreWorkerTaskInterface::SubmitTask(const RayFunction &function,
                                            const std::vector<TaskArg> &args,
                                            const TaskOptions &task_options,
                                            std::vector<ObjectID> *return_ids) {
-  auto &context = core_worker_.worker_context_;
+  auto &context = worker_context_;
   auto next_task_index = context.GetNextTaskIndex();
   const auto task_id = GenerateTaskId(context.GetCurrentJobID(),
                                       context.GetCurrentTaskID(), next_task_index);
@@ -116,12 +116,11 @@ Status CoreWorkerTaskInterface::SubmitTask(const RayFunction &function,
   }
 
   auto task_arguments = BuildTaskArguments(args);
-  auto language = ToRayletTaskLanguage(function.language);
 
   ray::raylet::TaskSpecification spec(context.GetCurrentJobID(),
                                       context.GetCurrentTaskID(), next_task_index,
                                       task_arguments, num_returns, task_options.resources,
-                                      language, function.function_descriptor);
+                                      function.language, function.function_descriptor);
 
   std::vector<ObjectID> execution_dependencies;
   TaskSpec task(std::move(spec), execution_dependencies);
@@ -132,7 +131,7 @@ Status CoreWorkerTaskInterface::CreateActor(
     const RayFunction &function, const std::vector<TaskArg> &args,
     const ActorCreationOptions &actor_creation_options,
     std::unique_ptr<ActorHandle> *actor_handle) {
-  auto &context = core_worker_.worker_context_;
+  auto &context = worker_context_;
   auto next_task_index = context.GetNextTaskIndex();
   const auto task_id = GenerateTaskId(context.GetCurrentJobID(),
                                       context.GetCurrentTaskID(), next_task_index);
@@ -147,7 +146,6 @@ Status CoreWorkerTaskInterface::CreateActor(
   (*actor_handle)->SetActorCursor(return_ids[0]);
 
   auto task_arguments = BuildTaskArguments(args);
-  auto language = ToRayletTaskLanguage(function.language);
 
   // Note that the caller is supposed to specify required placement resources
   // correctly via actor_creation_options.resources.
@@ -155,8 +153,8 @@ Status CoreWorkerTaskInterface::CreateActor(
       context.GetCurrentJobID(), context.GetCurrentTaskID(), next_task_index,
       actor_creation_id, ObjectID::Nil(), actor_creation_options.max_reconstructions,
       ActorID::Nil(), ActorHandleID::Nil(), 0, {}, task_arguments, 1,
-      actor_creation_options.resources, actor_creation_options.resources, language,
-      function.function_descriptor);
+      actor_creation_options.resources, actor_creation_options.resources,
+      function.language, function.function_descriptor);
 
   std::vector<ObjectID> execution_dependencies;
   TaskSpec task(std::move(spec), execution_dependencies);
@@ -168,7 +166,7 @@ Status CoreWorkerTaskInterface::SubmitActorTask(ActorHandle &actor_handle,
                                                 const std::vector<TaskArg> &args,
                                                 const TaskOptions &task_options,
                                                 std::vector<ObjectID> *return_ids) {
-  auto &context = core_worker_.worker_context_;
+  auto &context = worker_context_;
   auto next_task_index = context.GetNextTaskIndex();
   const auto task_id = GenerateTaskId(context.GetCurrentJobID(),
                                       context.GetCurrentTaskID(), next_task_index);
@@ -184,7 +182,6 @@ Status CoreWorkerTaskInterface::SubmitActorTask(ActorHandle &actor_handle,
       ObjectID::FromBinary(actor_handle.ActorID().Binary());
 
   auto task_arguments = BuildTaskArguments(args);
-  auto language = ToRayletTaskLanguage(function.language);
 
   std::unique_lock<std::mutex> guard(actor_handle.mutex_);
 
@@ -193,7 +190,7 @@ Status CoreWorkerTaskInterface::SubmitActorTask(ActorHandle &actor_handle,
       ActorID::Nil(), actor_creation_dummy_object_id, 0, actor_handle.ActorID(),
       actor_handle.ActorHandleID(), actor_handle.IncreaseTaskCounter(),
       actor_handle.NewActorHandles(), task_arguments, num_returns, task_options.resources,
-      task_options.resources, language, function.function_descriptor);
+      task_options.resources, function.language, function.function_descriptor);
 
   std::vector<ObjectID> execution_dependencies;
   execution_dependencies.push_back(actor_handle.ActorCursor());
diff --git a/src/ray/core_worker/task_interface.h b/src/ray/core_worker/task_interface.h
index 15839d72d..75bd9cc64 100644
--- a/src/ray/core_worker/task_interface.h
+++ b/src/ray/core_worker/task_interface.h
@@ -5,6 +5,7 @@
 #include "ray/common/id.h"
 #include "ray/common/status.h"
 #include "ray/core_worker/common.h"
+#include "ray/core_worker/context.h"
 #include "ray/core_worker/transport/transport.h"
 #include "ray/protobuf/core_worker.pb.h"
 #include "ray/raylet/task.h"
@@ -44,7 +45,7 @@ struct ActorCreationOptions {
 class ActorHandle {
  public:
   ActorHandle(const ActorID &actor_id, const ActorHandleID &actor_handle_id,
-              const ray::rpc::Language actor_language,
+              const ::Language actor_language,
               const std::vector<std::string> &actor_creation_task_function_descriptor);
 
   ActorHandle(const ActorHandle &other);
@@ -56,7 +57,7 @@ class ActorHandle {
   ray::ActorHandleID ActorHandleID() const;
 
   /// Language of the actor.
-  ray::rpc::Language ActorLanguage() const;
+  ::Language ActorLanguage() const;
 
   // Function descriptor of actor creation task.
   std::vector<std::string> ActorCreationTaskFunctionDescriptor() const;
@@ -110,7 +111,7 @@ class ActorHandle {
 /// submission.
 class CoreWorkerTaskInterface {
  public:
-  CoreWorkerTaskInterface(CoreWorker &core_worker);
+  CoreWorkerTaskInterface(WorkerContext &worker_context, RayletClient &raylet_client);
 
   /// Submit a normal task.
   ///
@@ -146,10 +147,6 @@ class CoreWorkerTaskInterface {
                          const TaskOptions &task_options,
                          std::vector<ObjectID> *return_ids);
 
- private:
-  /// Reference to the parent CoreWorker instance.
-  CoreWorker &core_worker_;
-
  private:
   /// Build the arguments for a task spec.
   ///
@@ -158,6 +155,9 @@ class CoreWorkerTaskInterface {
   std::vector<std::shared_ptr<raylet::TaskArgument>> BuildTaskArguments(
       const std::vector<TaskArg> &args);
 
+  /// Reference to the parent CoreWorker's context.
+  WorkerContext &worker_context_;
+
   /// All the task submitters supported.
   std::unordered_map<int, std::unique_ptr<CoreWorkerTaskSubmitter>> task_submitters_;
 };