diff --git a/sdk/src/main/java/io/dapr/actors/DaprClientBuilder.java b/sdk/src/main/java/io/dapr/actors/AbstractClientBuilder.java
similarity index 57%
rename from sdk/src/main/java/io/dapr/actors/DaprClientBuilder.java
rename to sdk/src/main/java/io/dapr/actors/AbstractClientBuilder.java
index 4ac91f30a1..5af3cc78ac 100644
--- a/sdk/src/main/java/io/dapr/actors/DaprClientBuilder.java
+++ b/sdk/src/main/java/io/dapr/actors/AbstractClientBuilder.java
@@ -1,58 +1,49 @@
-/*
- * Copyright (c) Microsoft Corporation.
- * Licensed under the MIT License.
- */
-
-package io.dapr.actors;
-
-import okhttp3.OkHttpClient;
-
-/**
- * Builds an instance of DaprAsyncClient or DaprClient.
- */
-class DaprClientBuilder {
-
-    /**
-     * Default port for Dapr after checking environment variable.
-     */
-    private int port = DaprClientBuilder.GetEnvPortOrDefault();
-
-    /**
-     * Builds an async client.
-     * @return Builds an async client.
-     */
-    public DaprAsyncClient buildAsyncClient() {
-        OkHttpClient.Builder builder = new OkHttpClient.Builder();
-        // TODO: Expose configurations for OkHttpClient or com.microsoft.rest.RestClient.
-        return new DaprHttpAsyncClient(this.port, builder.build());
-    }
-
-    /**
-     * Overrides the port.
-     * @param port New port.
-     * @return This instance.
-     */
-    public DaprClientBuilder withPort(int port) {
-        this.port = port;
-        return this;
-    }
-
-    /**
-     * Tries to get a valid port from environment variable or returns default.
-     * @return Port defined in env variable or default.
-     */
-    private static int GetEnvPortOrDefault() {
-        String envPort = System.getenv(Constants.ENV_DAPR_HTTP_PORT);
-        if (envPort == null) {
-            return Constants.DEFAULT_PORT;
-        }
-
-        try {
-            return Integer.parseInt(envPort.trim());
-        } catch (NumberFormatException e) {
-            e.printStackTrace();
-        }
-
-        return Constants.DEFAULT_PORT;
-    }
-}
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.actors;
+
+import okhttp3.OkHttpClient;
+import io.dapr.actors.*;
+
+/**
+ * Base class for client builders
+ */
+public abstract class AbstractClientBuilder {
+
+    /**
+     * Default port for Dapr after checking environment variable.
+     */
+    private int port = AbstractClientBuilder.GetEnvPortOrDefault();
+
+    /**
+     * Overrides the port.
+     * @param port New port.
+     * @return This instance.
+     */
+    public AbstractClientBuilder withPort(int port) {
+        this.port = port;
+        return this;
+    }
+
+    /**
+     * Tries to get a valid port from environment variable or returns default.
+     * @return Port defined in env variable or default.
+     */
+    protected static int GetEnvPortOrDefault() {
+        String envPort = System.getenv(Constants.ENV_DAPR_HTTP_PORT);
+        if (envPort == null) {
+            return Constants.DEFAULT_PORT;
+        }
+
+        try {
+            return Integer.parseInt(envPort.trim());
+        } catch (NumberFormatException e) {
+            e.printStackTrace();
+        }
+
+        return Constants.DEFAULT_PORT;
+    }
+}
diff --git a/sdk/src/main/java/io/dapr/actors/DaprHttpAsyncClient.java b/sdk/src/main/java/io/dapr/actors/AbstractDaprClient.java
similarity index 51%
rename from sdk/src/main/java/io/dapr/actors/DaprHttpAsyncClient.java
rename to sdk/src/main/java/io/dapr/actors/AbstractDaprClient.java
index b4e153e5d8..2be14579b2 100644
--- a/sdk/src/main/java/io/dapr/actors/DaprHttpAsyncClient.java
+++ b/sdk/src/main/java/io/dapr/actors/AbstractDaprClient.java
@@ -1,206 +1,131 @@
-/*
- * Copyright (c) Microsoft Corporation.
- * Licensed under the MIT License.
- */
-
-package io.dapr.actors;
-
-import com.fasterxml.jackson.databind.ObjectMapper;
-import okhttp3.*;
-import reactor.core.publisher.Mono;
-
-import java.io.IOException;
-import java.net.URL;
-import java.util.UUID;
-
-/**
- * Http client to call Dapr's API for actors.
- */
-class DaprHttpAsyncClient implements DaprAsyncClient {
-
-    /**
-     * Defines the standard application/json type for HTTP calls in Dapr.
-     */
-    private static final MediaType MEDIA_TYPE_APPLICATION_JSON = MediaType.get("application/json; charset=utf-8");
-
-    /**
-     * Shared object representing an empty request body in JSON.
-     */
-    private static final RequestBody REQUEST_BODY_EMPTY_JSON = RequestBody.create(MEDIA_TYPE_APPLICATION_JSON, "");
-
-    /**
-     * JSON Object Mapper.
-     */
-    private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
-    /**
-     * Base Url for calling Dapr. (e.g. http://localhost:3500/)
-     */
-    private final String baseUrl;
-
-    /**
-     * Http client used for all API calls.
-     */
-    private final OkHttpClient httpClient;
-
-    /**
-     * Creates a new instance of {@link DaprHttpAsyncClient}.
-     * @param port Port for calling Dapr. (e.g. 3500)
-     * @param httpClient RestClient used for all API calls in this new instance.
-     */
-    DaprHttpAsyncClient(int port, OkHttpClient httpClient)
-    {
-        this.baseUrl = String.format("http://%s:%d/", Constants.DEFAULT_HOSTNAME, port);;
-        this.httpClient = httpClient;
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Mono<String> invokeActorMethod(String actorType, String actorId, String methodName, String jsonPayload) {
-        String url = String.format(Constants.ACTOR_METHOD_RELATIVE_URL_FORMAT, actorType, actorId, methodName);
-        return invokeAPI("PUT", url, jsonPayload);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Mono<String> getState(String actorType, String actorId, String keyName) {
-        String url = String.format(Constants.ACTOR_STATE_KEY_RELATIVE_URL_FORMAT, actorType, actorId, keyName);
-        return invokeAPI("GET", url, null);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Mono<Void> removeState(String actorType, String actorId, String keyName) {
-        String url = String.format(Constants.ACTOR_STATE_KEY_RELATIVE_URL_FORMAT, actorType, actorId, keyName);
-        return invokeAPIVoid("DELETE", url, null);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Mono<Void> saveStateTransactionally(String actorType, String actorId, String data) {
-        String url = String.format(Constants.ACTOR_STATE_RELATIVE_URL_FORMAT, actorType, actorId);
-        return invokeAPIVoid("PUT", url, data);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Mono<Void> registerReminder(String actorType, String actorId, String reminderName, String data) {
-        String url = String.format(Constants.ACTOR_REMINDER_RELATIVE_URL_FORMAT, actorType, actorId, reminderName);
-        return invokeAPIVoid("PUT", url, data);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Mono<Void> unregisterReminder(String actorType, String actorId, String reminderName) {
-        String url = String.format(Constants.ACTOR_REMINDER_RELATIVE_URL_FORMAT, actorType, actorId, reminderName);
-        return invokeAPIVoid("DELETE", url, null);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Mono<Void> registerTimer(String actorType, String actorId, String timerName, String data) {
-        String url = String.format(Constants.ACTOR_TIMER_RELATIVE_URL_FORMAT, actorType, actorId, timerName);
-        return invokeAPIVoid("PUT", url, data);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Mono<Void> unregisterTimerAsync(String actorType, String actorId, String timerName) {
-        String url = String.format(Constants.ACTOR_TIMER_RELATIVE_URL_FORMAT, actorType, actorId, timerName);
-        return invokeAPIVoid("DELETE", url, null);
-    }
-
-    /**
-     * Invokes an API asynchronously that returns Void.
-     * @param method HTTP method.
-     * @param urlString url as String.
-     * @param json JSON payload or null.
-     * @return Asynchronous Void
-     */
-    private final Mono<Void> invokeAPIVoid(String method, String urlString, String json) {
-        return this.invokeAPI(method, urlString, json).then();
-    }
-
-    /**
-     * Invokes an API asynchronously that returns a text payload.
-     * @param method HTTP method.
-     * @param urlString url as String.
-     * @param json JSON payload or null.
-     * @return Asynchronous text
-     */
-    private final Mono<String> invokeAPI(String method, String urlString, String json) {
-        return Mono.fromSupplier(() -> {
-            try {
-                return tryInvokeAPI(method, urlString, json);
-            } catch (IOException e) {
-                e.printStackTrace();
-                throw new RuntimeException(e);
-            }
-        });
-    }
-
-    /**
-     * Invokes an API synchronously and returns a text payload.
-     * @param method HTTP method.
-     * @param urlString url as String.
-     * @param json JSON payload or null.
-     * @return text
-     */
-    private final String tryInvokeAPI(String method, String urlString, String json) throws IOException {
-        String requestId = UUID.randomUUID().toString();
-        RequestBody body = json != null ? RequestBody.create(MEDIA_TYPE_APPLICATION_JSON, json) : REQUEST_BODY_EMPTY_JSON;
-
-        Request request = new Request.Builder()
-                .url(new URL(this.baseUrl + urlString))
-                .method(method, body)
-                .addHeader(Constants.HEADER_DAPR_REQUEST_ID, requestId)
-                .build();
-
-        // TODO: make this call async as well.
-        Response response = this.httpClient.newCall(request).execute();
-        if (!response.isSuccessful())
-        {
-            DaprError error = parseDaprError(response.body().string());
-            if ((error != null) && (error.getErrorCode() != null) && (error.getMessage() != null))  {
-                throw new DaprException(error);
-            }
-
-            throw new DaprException("UNKNOWN", String.format("Dapr's Actor API %s failed with return code %d %s", urlString, response.code()));
-        }
-
-        return response.body().string();
-    }
-
-    /**
-     * Tries to parse an error from Dapr response body.
-     * @param json Response body from Dapr.
-     * @return DaprError or null if could not parse.
-     */
-    private static DaprError parseDaprError(String json) {
-        if (json == null) {
-            return null;
-        }
-
-        try {
-            return OBJECT_MAPPER.readValue(json, DaprError.class);
-        } catch (IOException e) {
-            e.printStackTrace();
-            return null;
-        }
-    }
-}
+package io.dapr.actors;
+
+
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import okhttp3.*;
+import reactor.core.publisher.Mono;
+
+import java.io.IOException;
+import java.net.URL;
+import java.util.UUID;
+
+// base class of hierarchy
+public abstract class AbstractDaprClient {
+    /**
+     * Defines the standard application/json type for HTTP calls in Dapr.
+     */
+    private static final MediaType MEDIA_TYPE_APPLICATION_JSON = MediaType.get("application/json; charset=utf-8");
+
+    /**
+     * Shared object representing an empty request body in JSON.
+     */
+    private static final RequestBody REQUEST_BODY_EMPTY_JSON = RequestBody.create(MEDIA_TYPE_APPLICATION_JSON, "");
+
+    /**
+     * JSON Object Mapper.
+     */
+    private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
+
+    /**
+     * The base url used for form urls.  This is typically "http://localhost:3500".
+     */
+    private final String baseUrl;
+
+    /**
+     * Http client used for all API calls.
+     */
+    private final OkHttpClient httpClient;
+
+    /**
+     * Creates a new instance of {@link AbstractDaprClient}.
+     * @param port Port for calling Dapr. (e.g. 3500)
+     * @param httpClient RestClient used for all API calls in this new instance.
+     */
+    public AbstractDaprClient(int port, OkHttpClient httpClient)
+    {
+        this.baseUrl = String.format("http://%s:%d/", Constants.DEFAULT_HOSTNAME, port);;
+        this.httpClient = httpClient;
+    }
+
+    // common methods
+    /**
+     * Invokes an API asynchronously that returns Void.
+     * @param method HTTP method.
+     * @param urlString url as String.
+     * @param json JSON payload or null.
+     * @return Asynchronous Void
+     */
+    protected final Mono<Void> invokeAPIVoid(String method, String urlString, String json) {
+        return this.invokeAPI(method, urlString, json).then();
+    }
+
+    /**
+     * Invokes an API asynchronously that returns a text payload.
+     * @param method HTTP method.
+     * @param urlString url as String.
+     * @param json JSON payload or null.
+     * @return Asynchronous text
+     */
+    protected final Mono<String> invokeAPI(String method, String urlString, String json) {
+        return Mono.fromSupplier(() -> {
+            try {
+                return tryInvokeAPI(method, urlString, json);
+            } catch (IOException e) {
+                e.printStackTrace();
+                throw new RuntimeException(e);
+            }
+        });
+    }
+
+    /**
+     * Invokes an API synchronously and returns a text payload.
+     * @param method HTTP method.
+     * @param urlString url as String.
+     * @param json JSON payload or null.
+     * @return text
+     */
+    protected final String tryInvokeAPI(String method, String urlString, String json) throws IOException {
+        String requestId = UUID.randomUUID().toString();
+        RequestBody body = json != null ? RequestBody.create(MEDIA_TYPE_APPLICATION_JSON, json) : REQUEST_BODY_EMPTY_JSON;
+
+        Request request = new Request.Builder()
+                .url(new URL(this.baseUrl + urlString))
+                .method(method, body)
+                .addHeader(Constants.HEADER_DAPR_REQUEST_ID, requestId)
+                .build();
+
+        // TODO: make this call async as well.
+        Response response = this.httpClient.newCall(request).execute();
+        if (!response.isSuccessful())
+        {
+            DaprError error = parseDaprError(response.body().string());
+            if ((error != null) && (error.getErrorCode() != null) && (error.getMessage() != null))  {
+                throw new DaprException(error);
+            }
+
+            throw new DaprException("UNKNOWN", String.format("Dapr's Actor API %s failed with return code %d %s", urlString, response.code()));
+        }
+
+        return response.body().string();
+    }
+
+    /**
+     * Tries to parse an error from Dapr response body.
+     * @param json Response body from Dapr.
+     * @return DaprError or null if could not parse.
+     */
+    protected static DaprError parseDaprError(String json) {
+        if (json == null) {
+            return null;
+        }
+
+        try {
+            return OBJECT_MAPPER.readValue(json, DaprError.class);
+        } catch (IOException e) {
+            e.printStackTrace();
+            return null;
+        }
+    }
+}
diff --git a/sdk/src/main/java/io/dapr/actors/ActorId.java b/sdk/src/main/java/io/dapr/actors/ActorId.java
new file mode 100644
index 0000000000..412f729452
--- /dev/null
+++ b/sdk/src/main/java/io/dapr/actors/ActorId.java
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.actors;
+
+/**
+ * Stub
+ */
+public class ActorId {
+    public ActorId(String id) {
+    }
+}
diff --git a/sdk/src/main/java/io/dapr/actors/ActorTrace.java b/sdk/src/main/java/io/dapr/actors/ActorTrace.java
new file mode 100644
index 0000000000..f3c7d5fea1
--- /dev/null
+++ b/sdk/src/main/java/io/dapr/actors/ActorTrace.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.actors;
+
+/**
+ * Stub
+ */
+public class ActorTrace {
+    public static void WriteInfo(String text) {
+        System.out.println(text);
+    }
+    
+    public static void WriteWarning(String text) {
+        System.out.println("Warning: " + text);
+    }
+    
+    public static void WriteError(String text) {
+        System.err.println(text);
+    }
+}
diff --git a/sdk/src/main/java/io/dapr/actors/Constants.java b/sdk/src/main/java/io/dapr/actors/Constants.java
index 66f4dbfc3f..86ea80fac8 100644
--- a/sdk/src/main/java/io/dapr/actors/Constants.java
+++ b/sdk/src/main/java/io/dapr/actors/Constants.java
@@ -8,7 +8,7 @@
 /**
  * Useful constants for the Dapr's Actor SDK.
  */
-final class Constants {
+public final class Constants {
 
     /**
      * Dapr API used in this client.
diff --git a/sdk/src/main/java/io/dapr/actors/DaprException.java b/sdk/src/main/java/io/dapr/actors/DaprException.java
index 2c7b8348f7..50ad94a9b9 100644
--- a/sdk/src/main/java/io/dapr/actors/DaprException.java
+++ b/sdk/src/main/java/io/dapr/actors/DaprException.java
@@ -10,7 +10,7 @@
 /**
  * A Dapr's specific exception.
  */
-class DaprException extends IOException {
+public class DaprException extends IOException {
 
     /**
      * Dapr's error code for this exception.
@@ -39,7 +39,7 @@ class DaprException extends IOException {
      * Returns the exception's error code.
      * @return Error code.
      */
-    String getErrorCode() {
+    public String getErrorCode() {
         return this.errorCode;
     }
 }
diff --git a/sdk/src/main/java/io/dapr/actors/client/ActorProxyAsyncClient.java b/sdk/src/main/java/io/dapr/actors/client/ActorProxyAsyncClient.java
new file mode 100644
index 0000000000..b4f6b0bfda
--- /dev/null
+++ b/sdk/src/main/java/io/dapr/actors/client/ActorProxyAsyncClient.java
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.actors.client;
+
+import reactor.core.publisher.Mono;
+
+/**
+ * Interface to invoke actor methods.
+ */
+interface ActorProxyAsyncClient {
+
+    /**
+     * Invokes an Actor method on Dapr.
+     * @param actorType Type of actor.
+     * @param actorId Actor Identifier.
+     * @param methodName Method name to invoke.
+     * @param jsonPayload Serialized body.
+     * @return Asynchronous result with the Actor's response.
+     */
+    Mono<String> invokeActorMethod(String actorType, String actorId, String methodName, String jsonPayload);
+}
diff --git a/sdk/src/main/java/io/dapr/actors/client/ActorProxyClientBuilder.java b/sdk/src/main/java/io/dapr/actors/client/ActorProxyClientBuilder.java
new file mode 100644
index 0000000000..4f7d88fb9f
--- /dev/null
+++ b/sdk/src/main/java/io/dapr/actors/client/ActorProxyClientBuilder.java
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.actors.client;
+
+import okhttp3.OkHttpClient;
+import io.dapr.actors.*;
+
+/**
+ * Builds an instance of ActorProxyAsyncClient.
+ */
+class ActorProxyClientBuilder extends AbstractClientBuilder {
+
+    /**
+     * Default port for Dapr after checking environment variable.
+     */
+    private int port = ActorProxyClientBuilder.GetEnvPortOrDefault();
+
+    /**
+     * Builds an async client.
+     * @return Builds an async client.
+     */
+    public ActorProxyAsyncClient buildAsyncClient() {
+        OkHttpClient.Builder builder = new OkHttpClient.Builder();
+        // TODO: Expose configurations for OkHttpClient or com.microsoft.rest.RestClient.
+        return new ActorProxyHttpAsyncClient(this.port, builder.build());
+    }
+}
diff --git a/sdk/src/main/java/io/dapr/actors/client/ActorProxyHttpAsyncClient.java b/sdk/src/main/java/io/dapr/actors/client/ActorProxyHttpAsyncClient.java
new file mode 100644
index 0000000000..2b44b35eab
--- /dev/null
+++ b/sdk/src/main/java/io/dapr/actors/client/ActorProxyHttpAsyncClient.java
@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.actors.client;
+
+import io.dapr.actors.*;
+import io.dapr.actors.AbstractDaprClient;
+import okhttp3.*;
+import reactor.core.publisher.Mono;
+
+/**
+ * Http client to call actors methods.
+ */
+class ActorProxyHttpAsyncClient extends AbstractDaprClient implements ActorProxyAsyncClient {
+    /**
+     * Creates a new instance of {@link ActorProxyHttpAsyncClient}.
+     * @param port Port for calling Dapr. (e.g. 3500)
+     * @param httpClient RestClient used for all API calls in this new instance.
+     */
+    public ActorProxyHttpAsyncClient(int port, OkHttpClient httpClient)
+    {
+        super(port, httpClient);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public Mono<String> invokeActorMethod(String actorType, String actorId, String methodName, String jsonPayload) {
+        String url = String.format(Constants.ACTOR_METHOD_RELATIVE_URL_FORMAT, actorType, actorId, methodName);
+        return super.invokeAPI("PUT", url, jsonPayload);
+    }
+}
diff --git a/sdk/src/main/java/io/dapr/actors/runtime/AbstractActor.java b/sdk/src/main/java/io/dapr/actors/runtime/AbstractActor.java
index 81eeaac341..1162c254f2 100644
--- a/sdk/src/main/java/io/dapr/actors/runtime/AbstractActor.java
+++ b/sdk/src/main/java/io/dapr/actors/runtime/AbstractActor.java
@@ -6,7 +6,7 @@
 package io.dapr.actors.runtime;
 
 /**
- * TODO
+ * TODO - this is the base class Actor implementations (user code) will extend.
  */
 public abstract class AbstractActor {
 }
diff --git a/sdk/src/main/java/io/dapr/actors/runtime/Actor.java b/sdk/src/main/java/io/dapr/actors/runtime/Actor.java
index 25c8193252..abc4af567e 100644
--- a/sdk/src/main/java/io/dapr/actors/runtime/Actor.java
+++ b/sdk/src/main/java/io/dapr/actors/runtime/Actor.java
@@ -6,7 +6,7 @@
 package io.dapr.actors.runtime;
 
 /**
- * TODO
+ * TODO - this is the interface user Actor methods should implement to receive calls.
  */
 public interface Actor {
 }
diff --git a/sdk/src/main/java/io/dapr/actors/runtime/ActorManager.java b/sdk/src/main/java/io/dapr/actors/runtime/ActorManager.java
new file mode 100644
index 0000000000..3974dd43a6
--- /dev/null
+++ b/sdk/src/main/java/io/dapr/actors/runtime/ActorManager.java
@@ -0,0 +1,11 @@
+package io.dapr.actors.runtime;
+
+// stub
+public class ActorManager {
+
+    public ActorManager(ActorService actorService) {
+
+    }
+}
+
+
diff --git a/sdk/src/main/java/io/dapr/actors/runtime/ActorRuntime.java b/sdk/src/main/java/io/dapr/actors/runtime/ActorRuntime.java
new file mode 100644
index 0000000000..6574cb8658
--- /dev/null
+++ b/sdk/src/main/java/io/dapr/actors/runtime/ActorRuntime.java
@@ -0,0 +1,186 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.actors.runtime;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Set;
+import java.util.function.Function;
+
+import io.dapr.actors.*;
+
+/**
+ * Contains methods to register actor types. Registering the types allows the runtime to create instances of the actor.
+ */
+public class ActorRuntime {
+    /**
+     *  Gets an instance to the ActorRuntime.  There is only 1.
+     */
+    private static volatile ActorRuntime instance;
+
+    /**
+     *  A client used to communicate from the actor to the Dapr runtime.
+     */
+    private static AppToDaprAsyncClient appToDaprAsyncClient;
+
+    /**
+     *  A trace type used when logging.
+     */
+    private static final String TraceType = "ActorRuntime";
+
+    /**
+     *  Map of ActorType --> ActorManager.
+     */
+    private final HashMap<String, ActorManager> actorManagers;
+
+    /**
+     * The default constructor.  This should not be called directly.
+     * @throws IllegalStateException
+     */
+    private ActorRuntime() throws IllegalStateException{
+        if (instance != null) {
+            throw new IllegalStateException("ActorRuntime should only be constructed once");
+        }
+
+        this.actorManagers = new HashMap<String, ActorManager>();
+        appToDaprAsyncClient = new AppToDaprClientBuilder().buildAsyncClient();
+    }
+
+    /**
+     * Returns an ActorRuntime object.
+     * @return An ActorRuntime object.
+     */
+    public static ActorRuntime getInstance() {
+        if (instance == null) {
+            synchronized (ActorRuntime.class) {
+                if (instance == null) {
+                    instance = new ActorRuntime();
+                }
+            }
+        }
+
+        return  instance;
+    }
+
+    /**
+     *
+     * @return Actor type names registered with the runtime.
+     */
+    public Collection<String> getRegisteredActorTypes() {
+        return Collections.unmodifiableCollection(this.actorManagers.keySet());
+    }
+
+    /**
+     * Registers an actor with the runtime.
+     * @param clazz The type of actor.
+     */
+    public <T extends AbstractActor> void RegisterActor(Class<T> clazz) {
+        RegisterActor(clazz, null);
+    }
+
+    /**
+     * Registers an actor with the runtime.
+     * @param clazz The type of actor.
+     * @param actorServiceFactory An optional delegate to create actor service. This can be used for dependency injection into actors.
+     */
+    public <T extends AbstractActor> void RegisterActor(Class<T> clazz, Function<ActorTypeInformation, ActorService> actorServiceFactory)
+    {
+        ActorTypeInformation actorTypeInfo = ActorTypeInformation.create(clazz);
+
+        ActorService actorService;
+        if (actorServiceFactory != null)
+        {
+            actorService = actorServiceFactory.apply(actorTypeInfo);
+        }
+        else
+        {
+            actorService = new ActorService(actorTypeInfo);
+        }
+
+        // Create ActorManagers, override existing entry if registered again.
+        synchronized (this.actorManagers) {
+            this.actorManagers.put(actorTypeInfo.getName(), new ActorManager(actorService));
+        }
+    }
+
+    /**
+     * Activates an actor for an actor type with given actor id.
+     * @param actorTypeName Actor type name to activate the actor for.
+     * @param actorId Actor id for the actor to be activated.
+     */
+    static void Activate(String actorTypeName, String actorId)
+    {
+        // uncomment when ActorManager implemented
+        // return instance.GetActorManager(actorTypeName).ActivateActor(new ActorId(actorId));
+    }
+
+    /**
+     * Deactivates an actor for an actor type with given actor id.
+     * @param actorTypeName Actor type name to deactivate the actor for.
+     * @param actorId Actor id for the actor to be deactivated.
+     */
+    static void Deactivate(String actorTypeName, String actorId)
+    {
+        // uncomment when ActorManager implemented
+        // return instance.GetActorManager(actorTypeName).DeactivateActor(new ActorId(actorId));
+    }
+
+    /**
+     *  Invokes the specified method for the actor, this is mainly used for cross language invocation.
+     * @param actorTypeName Actor type name to invoke the method for.
+     * @param actorId Actor id for the actor for which method will be invoked.
+     * @param actorMethodName Method name on actor type which will be invoked.
+     * @param requestBodyStream Payload for the actor method.
+     * @param responseBodyStream Response for the actor method.
+     * @return
+     */
+    static void Dispatch(String actorTypeName, String actorId, String actorMethodName, byte[] requestBodyStream, byte[] responseBodyStream)
+    {
+        // uncomment when ActorManager implemented
+        // return instance.GetActorManager(actorTypeName).Dispatch(new ActorId(actorId), actorMethodName, requestBodyStream, responseBodyStream);
+    }
+
+    /**
+     * Fires a reminder for the Actor.
+     * @param actorTypeName Actor type name to invoke the method for.
+     * @param actorId Actor id for the actor for which method will be invoked.
+     * @param reminderName The name of reminder provided during registration.
+     * @param requestBodyStream Payload for the actor method
+     */
+    static void FireReminder(String actorTypeName, String actorId, String reminderName, byte[] requestBodyStream)
+    {
+        // uncomment when ActorManager implemented
+        // return instance.GetActorManager(actorTypeName).FireReminder(new ActorId(actorId), reminderName, requestBodyStream);
+    }
+
+    /**
+     * Fires a timer for the Actor.
+     * @param actorTypeName Actor type name to invoke the method for.
+     * @param actorId Actor id for the actor for which method will be invoked.
+     * @param timerName The name of timer provided during registration.
+     */
+    static void FireTimer(String actorTypeName, String actorId, String timerName)
+    {
+        // uncomment when ActorManager implemented
+        // return instance.GetActorManager(actorTypeName).FireTimerAsync(new ActorId(actorId), timerName);
+    }
+
+    private ActorManager GetActorManager(String actorTypeName) throws IllegalStateException
+    {
+        ActorManager actorManager = this.actorManagers.get(actorTypeName);
+
+        if (actorManager == null)
+        {
+            String errorMsg = String.format("Actor type %s is not registered with Actor runtime.", actorTypeName);
+
+            ActorTrace.WriteError(errorMsg);
+            throw new IllegalStateException(errorMsg);
+        }
+
+        return actorManager;
+    }
+}
\ No newline at end of file
diff --git a/sdk/src/main/java/io/dapr/actors/runtime/ActorService.java b/sdk/src/main/java/io/dapr/actors/runtime/ActorService.java
new file mode 100644
index 0000000000..110f6fc248
--- /dev/null
+++ b/sdk/src/main/java/io/dapr/actors/runtime/ActorService.java
@@ -0,0 +1,8 @@
+package io.dapr.actors.runtime;
+
+// stub
+public class ActorService {
+    public ActorService(ActorTypeInformation actorTypeInformation) {
+
+    }
+}
diff --git a/sdk/src/main/java/io/dapr/actors/DaprAsyncClient.java b/sdk/src/main/java/io/dapr/actors/runtime/AppToDaprAsyncClient.java
similarity index 69%
rename from sdk/src/main/java/io/dapr/actors/DaprAsyncClient.java
rename to sdk/src/main/java/io/dapr/actors/runtime/AppToDaprAsyncClient.java
index 9b0345f429..66fe3d1757 100644
--- a/sdk/src/main/java/io/dapr/actors/DaprAsyncClient.java
+++ b/sdk/src/main/java/io/dapr/actors/runtime/AppToDaprAsyncClient.java
@@ -1,89 +1,71 @@
-/*
- * Copyright (c) Microsoft Corporation.
- * Licensed under the MIT License.
- */
-
-package io.dapr.actors;
-
-import reactor.core.publisher.Mono;
-
-/**
- * Interface for interacting with Dapr runtime.
- */
-interface DaprAsyncClient {
-
-    /**
-     * Invokes an Actor method on Dapr.
-     * @param actorType Type of actor.
-     * @param actorId Actor Identifier.
-     * @param methodName Method name to invoke.
-     * @param jsonPayload Serialized body.
-     * @return Asynchronous result with the Actor's response.
-     */
-    Mono<String> invokeActorMethod(String actorType, String actorId, String methodName, String jsonPayload);
-
-    /**
-     * Gets a state from Dapr's Actor.
-     * @param actorType Type of actor.
-     * @param actorId Actor Identifier.
-     * @param keyName State name.
-     * @return Asynchronous result with current state value.
-     */
-    Mono<String> getState(String actorType, String actorId, String keyName);
-
-    /**
-     * Removes Actor state in Dapr. This is temporary until the Dapr runtime implements the Batch state update.
-     * @param actorType Type of actor.
-     * @param actorId Actor Identifier.
-     * @param keyName State name.
-     * @return Asynchronous void result.
-     */
-    Mono<Void> removeState(String actorType, String actorId, String keyName);
-
-    /**
-     * Saves state batch to Dapr.
-     * @param actorType Type of actor.
-     * @param actorId Actor Identifier.
-     * @param data State to be saved.
-     * @return Asynchronous void result.
-     */
-    Mono<Void> saveStateTransactionally(String actorType, String actorId, String data);
-
-    /**
-     * Register a reminder.
-     * @param actorType Type of actor.
-     * @param actorId Actor Identifier.
-     * @param reminderName Name of reminder to be registered.
-     * @param data JSON reminder data as per Dapr's spec.
-     * @return Asynchronous void result.
-     */
-    Mono<Void> registerReminder(String actorType, String actorId, String reminderName, String data);
-
-    /**
-     * Unregisters a reminder.
-     * @param actorType Type of actor.
-     * @param actorId Actor Identifier.
-     * @param reminderName Name of reminder to be unregistered.
-     * @return Asynchronous void result.
-     */
-    Mono<Void> unregisterReminder(String actorType, String actorId, String reminderName);
-
-    /**
-     * Registers a timer.
-     * @param actorType Type of actor.
-     * @param actorId Actor Identifier.
-     * @param timerName Name of timer to be registered.
-     * @param data JSON reminder data as per Dapr's spec.
-     * @return Asynchronous void result.
-     */
-    Mono<Void> registerTimer(String actorType, String actorId, String timerName, String data);
-
-    /**
-     * Unregisters a timer.
-     * @param actorType Type of actor.
-     * @param actorId Actor Identifier.
-     * @param timerName Name of timer to be unregistered.
-     * @return Asynchronous void result.
-     */
-    Mono<Void> unregisterTimerAsync(String actorType, String actorId, String timerName);
-}
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.actors.runtime;
+
+import reactor.core.publisher.Mono;
+
+
+/**
+ * Interface for interacting from the actor app to the Dapr runtime.
+ */
+interface AppToDaprAsyncClient {
+
+    /**
+     * Gets a state from Dapr's Actor.
+     * @param actorType Type of actor.
+     * @param actorId Actor Identifier.
+     * @param keyName State name.
+     * @return Asynchronous result with current state value.
+     */
+    Mono<String> getState(String actorType, String actorId, String keyName);
+
+    /**
+     * Saves state batch to Dapr.
+     * @param actorType Type of actor.
+     * @param actorId Actor Identifier.
+     * @param data State to be saved.
+     * @return Asynchronous void result.
+     */
+    Mono<Void> saveStateTransactionally(String actorType, String actorId, String data);
+
+    /**
+     * Register a reminder.
+     * @param actorType Type of actor.
+     * @param actorId Actor Identifier.
+     * @param reminderName Name of reminder to be registered.
+     * @param data JSON reminder data as per Dapr's spec.
+     * @return Asynchronous void result.
+     */
+    Mono<Void> registerReminder(String actorType, String actorId, String reminderName, String data);
+
+    /**
+     * Unregisters a reminder.
+     * @param actorType Type of actor.
+     * @param actorId Actor Identifier.
+     * @param reminderName Name of reminder to be unregistered.
+     * @return Asynchronous void result.
+     */
+    Mono<Void> unregisterReminder(String actorType, String actorId, String reminderName);
+
+    /**
+     * Registers a timer.
+     * @param actorType Type of actor.
+     * @param actorId Actor Identifier.
+     * @param timerName Name of timer to be registered.
+     * @param data JSON reminder data as per Dapr's spec.
+     * @return Asynchronous void result.
+     */
+    Mono<Void> registerTimer(String actorType, String actorId, String timerName, String data);
+
+    /**
+     * Unregisters a timer.
+     * @param actorType Type of actor.
+     * @param actorId Actor Identifier.
+     * @param timerName Name of timer to be unregistered.
+     * @return Asynchronous void result.
+     */
+    Mono<Void> unregisterTimerAsync(String actorType, String actorId, String timerName);
+}
diff --git a/sdk/src/main/java/io/dapr/actors/runtime/AppToDaprClientBuilder.java b/sdk/src/main/java/io/dapr/actors/runtime/AppToDaprClientBuilder.java
new file mode 100644
index 0000000000..1476057ca3
--- /dev/null
+++ b/sdk/src/main/java/io/dapr/actors/runtime/AppToDaprClientBuilder.java
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.actors.runtime;
+
+import okhttp3.OkHttpClient;
+import io.dapr.actors.*;
+
+/**
+ * Builds an instance of AppToDaprAsyncClient.
+ */
+class AppToDaprClientBuilder extends AbstractClientBuilder {
+
+    /**
+     * Default port for Dapr after checking environment variable.
+     */
+    private int port = AppToDaprClientBuilder.GetEnvPortOrDefault();
+
+    /**
+     * Builds an async client.
+     * @return Builds an async client.
+     */
+    public AppToDaprAsyncClient buildAsyncClient() {
+        OkHttpClient.Builder builder = new OkHttpClient.Builder();
+        // TODO: Expose configurations for OkHttpClient or com.microsoft.rest.RestClient.
+        return new AppToDaprHttpAsyncClient(this.port, builder.build());
+    }
+}
diff --git a/sdk/src/main/java/io/dapr/actors/runtime/AppToDaprHttpAsyncClient.java b/sdk/src/main/java/io/dapr/actors/runtime/AppToDaprHttpAsyncClient.java
new file mode 100644
index 0000000000..6c4041042b
--- /dev/null
+++ b/sdk/src/main/java/io/dapr/actors/runtime/AppToDaprHttpAsyncClient.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.actors.runtime;
+
+import io.dapr.actors.Constants;
+import io.dapr.actors.AbstractDaprClient;
+import okhttp3.*;
+import reactor.core.publisher.Mono;
+
+
+/**
+ * Http client to call Dapr's API for actors.
+ */
+//public class DaprHttpAsyncClient implements DaprAsyncClient {
+class AppToDaprHttpAsyncClient extends AbstractDaprClient implements AppToDaprAsyncClient {
+
+    /**
+     * Creates a new instance of {@link AppToDaprHttpAsyncClient}.
+     * @param port Port for calling Dapr. (e.g. 3500)
+     * @param httpClient RestClient used for all API calls in this new instance.
+     */
+    public AppToDaprHttpAsyncClient(int port, OkHttpClient httpClient)
+    {
+        super(port, httpClient);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public Mono<String> getState(String actorType, String actorId, String keyName) {
+        String url = String.format(Constants.ACTOR_STATE_KEY_RELATIVE_URL_FORMAT, actorType, actorId, keyName);
+        return super.invokeAPI("GET", url, null);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public Mono<Void> saveStateTransactionally(String actorType, String actorId, String data) {
+        String url = String.format(Constants.ACTOR_STATE_RELATIVE_URL_FORMAT, actorType, actorId);
+        return super.invokeAPIVoid("PUT", url, data);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public Mono<Void> registerReminder(String actorType, String actorId, String reminderName, String data) {
+        String url = String.format(Constants.ACTOR_REMINDER_RELATIVE_URL_FORMAT, actorType, actorId, reminderName);
+        return super.invokeAPIVoid("PUT", url, data);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public Mono<Void> unregisterReminder(String actorType, String actorId, String reminderName) {
+        String url = String.format(Constants.ACTOR_REMINDER_RELATIVE_URL_FORMAT, actorType, actorId, reminderName);
+        return super.invokeAPIVoid("DELETE", url, null);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public Mono<Void> registerTimer(String actorType, String actorId, String timerName, String data) {
+        String url = String.format(Constants.ACTOR_TIMER_RELATIVE_URL_FORMAT, actorType, actorId, timerName);
+        return super.invokeAPIVoid("PUT", url, data);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public Mono<Void> unregisterTimerAsync(String actorType, String actorId, String timerName) {
+        String url = String.format(Constants.ACTOR_TIMER_RELATIVE_URL_FORMAT, actorType, actorId, timerName);
+        return super.invokeAPIVoid("DELETE", url, null);
+    }
+}
diff --git a/sdk/src/test/java/io/dapr/actors/DaprHttpAsyncClientIT.java b/sdk/src/test/java/io/dapr/actors/client/DaprHttpAsyncClientIT.java
similarity index 89%
rename from sdk/src/test/java/io/dapr/actors/DaprHttpAsyncClientIT.java
rename to sdk/src/test/java/io/dapr/actors/client/DaprHttpAsyncClientIT.java
index 763f8e38b9..3096f13a89 100644
--- a/sdk/src/test/java/io/dapr/actors/DaprHttpAsyncClientIT.java
+++ b/sdk/src/test/java/io/dapr/actors/client/DaprHttpAsyncClientIT.java
@@ -1,42 +1,43 @@
-/*
- * Copyright (c) Microsoft Corporation.
- * Licensed under the MIT License.
- */
-
-package io.dapr.actors;
-
-import org.junit.Assert;
-import org.junit.Test;
-
-/**
- * Integration test for the HTTP Async Client.
- *
- * Requires Dapr running.
- */
-public class DaprHttpAsyncClientIT {
-
-    /**
-     * Checks if the error is correctly parsed when trying to invoke a function on an unknown actor type.
-     */
-    @Test(expected = RuntimeException.class)
-    public void invokeUnknownActor() {
-        DaprAsyncClient daprAsyncClient = new DaprClientBuilder().buildAsyncClient();
-        daprAsyncClient
-                .invokeActorMethod("ActorThatDoesNotExist", "100", "GetData", null)
-                .doOnError(x -> {
-                    Assert.assertTrue(x instanceof RuntimeException);
-                    RuntimeException runtimeException = (RuntimeException)x;
-
-                    Throwable cause = runtimeException.getCause();
-                    Assert.assertTrue(cause instanceof DaprException);
-                    DaprException daprException = (DaprException)cause;
-
-                    Assert.assertNotNull(daprException);
-                    Assert.assertEquals("ERR_INVOKE_ACTOR", daprException.getErrorCode());
-                    Assert.assertNotNull(daprException.getMessage());
-                    Assert.assertFalse(daprException.getMessage().isEmpty());
-                })
-                .doOnSuccess(x -> Assert.fail("This call should fail."))
-                .block();
-    }
-}
+/*
+ * Copyright (c) Microsoft Corporation.
+ * Licensed under the MIT License.
+ */
+
+package io.dapr.actors.client;
+
+import io.dapr.actors.*;
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Integration test for the HTTP Async Client.
+ *
+ * Requires Dapr running.
+ */
+public class DaprHttpAsyncClientIT {
+
+    /**
+     * Checks if the error is correctly parsed when trying to invoke a function on an unknown actor type.
+     */
+    @Test(expected = RuntimeException.class)
+    public void invokeUnknownActor() {
+        ActorProxyAsyncClient daprAsyncClient = new ActorProxyClientBuilder().buildAsyncClient();
+        daprAsyncClient
+                .invokeActorMethod("ActorThatDoesNotExist", "100", "GetData", null)
+                .doOnError(x -> {
+                    Assert.assertTrue(x instanceof RuntimeException);
+                    RuntimeException runtimeException = (RuntimeException)x;
+
+                    Throwable cause = runtimeException.getCause();
+                    Assert.assertTrue(cause instanceof DaprException);
+                    DaprException daprException = (DaprException)cause;
+
+                    Assert.assertNotNull(daprException);
+                    Assert.assertEquals("ERR_INVOKE_ACTOR", daprException.getErrorCode());
+                    Assert.assertNotNull(daprException.getMessage());
+                    Assert.assertFalse(daprException.getMessage().isEmpty());
+                })
+                .doOnSuccess(x -> Assert.fail("This call should fail."))
+                .block();
+    }
+}