diff --git a/application/src/main/java/org/thingsboard/server/service/job/task/DummyTaskProcessor.java b/application/src/main/java/org/thingsboard/server/service/job/task/DummyTaskProcessor.java
index 73a27a0012..361dbfbde1 100644
--- a/application/src/main/java/org/thingsboard/server/service/job/task/DummyTaskProcessor.java
+++ b/application/src/main/java/org/thingsboard/server/service/job/task/DummyTaskProcessor.java
@@ -23,10 +23,10 @@ import org.thingsboard.server.queue.task.TaskProcessor;
 
 @Component
 @RequiredArgsConstructor
-public class DummyTaskProcessor extends TaskProcessor<DummyTask> {
+public class DummyTaskProcessor extends TaskProcessor<DummyTask, Void> {
 
     @Override
-    public void process(DummyTask task) throws Exception {
+    public Void process(DummyTask task) throws Exception {
         if (task.getProcessingTimeMs() > 0) {
             Thread.sleep(task.getProcessingTimeMs());
         }
@@ -37,6 +37,7 @@ public class DummyTaskProcessor extends TaskProcessor<DummyTask> {
             String error = task.getErrors().get(task.getAttempt() - 1);
             throw new RuntimeException(error);
         }
+        return null;
     }
 
     @Override
diff --git a/common/queue/src/main/java/org/thingsboard/server/queue/task/TaskProcessor.java b/common/queue/src/main/java/org/thingsboard/server/queue/task/TaskProcessor.java
index f0ba542ab9..57dd46a6e5 100644
--- a/common/queue/src/main/java/org/thingsboard/server/queue/task/TaskProcessor.java
+++ b/common/queue/src/main/java/org/thingsboard/server/queue/task/TaskProcessor.java
@@ -43,7 +43,7 @@ import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
-public abstract class TaskProcessor<T extends Task> {
+public abstract class TaskProcessor<T extends Task, R> {
 
     protected final Logger log = LoggerFactory.getLogger(getClass());
 
@@ -135,7 +135,7 @@ public abstract class TaskProcessor<T extends Task> {
         }
     }
 
-    public abstract void process(T task) throws Exception;
+    public abstract R process(T task) throws Exception;
 
     private void reportSuccess(Task task) {
         TaskResult result = TaskResult.builder()
diff --git a/rest-client/src/main/java/org/thingsboard/rest/client/RestClient.java b/rest-client/src/main/java/org/thingsboard/rest/client/RestClient.java
index 4f7538d205..eb051b19e5 100644
--- a/rest-client/src/main/java/org/thingsboard/rest/client/RestClient.java
+++ b/rest-client/src/main/java/org/thingsboard/rest/client/RestClient.java
@@ -19,7 +19,9 @@ import com.auth0.jwt.JWT;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.google.common.base.Strings;
+import lombok.SneakyThrows;
 import org.apache.commons.io.IOUtils;
+import org.apache.commons.lang3.concurrent.LazyInitializer;
 import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.core.io.ByteArrayResource;
 import org.springframework.core.io.Resource;
@@ -55,9 +57,9 @@ import org.thingsboard.server.common.data.EntityType;
 import org.thingsboard.server.common.data.EntityView;
 import org.thingsboard.server.common.data.EntityViewInfo;
 import org.thingsboard.server.common.data.EventInfo;
-import org.thingsboard.server.common.data.ResourceExportData;
 import org.thingsboard.server.common.data.OtaPackage;
 import org.thingsboard.server.common.data.OtaPackageInfo;
+import org.thingsboard.server.common.data.ResourceExportData;
 import org.thingsboard.server.common.data.ResourceSubType;
 import org.thingsboard.server.common.data.SaveDeviceWithCredentialsRequest;
 import org.thingsboard.server.common.data.StringUtils;
@@ -205,7 +207,9 @@ public class RestClient implements Closeable {
     private static final String JWT_TOKEN_HEADER_PARAM = "X-Authorization";
     private static final long AVG_REQUEST_TIMEOUT = TimeUnit.SECONDS.toMillis(30);
     protected static final String ACTIVATE_TOKEN_REGEX = "/api/noauth/activate?activateToken=";
-    private final ExecutorService service = ThingsBoardExecutors.newWorkStealingPool(10, getClass());
+    private final LazyInitializer<ExecutorService> executor = LazyInitializer.<ExecutorService>builder()
+            .setInitializer(() -> ThingsBoardExecutors.newWorkStealingPool(10, getClass()))
+            .get();
     protected final RestTemplate restTemplate;
     protected final RestTemplate loginRestTemplate;
     protected final String baseURL;
@@ -223,22 +227,30 @@ public class RestClient implements Closeable {
     }
 
     public RestClient(RestTemplate restTemplate, String baseURL) {
+        this(restTemplate, baseURL, null);
+    }
+
+    public RestClient(RestTemplate restTemplate, String baseURL, String accessToken) {
         this.restTemplate = restTemplate;
         this.loginRestTemplate = new RestTemplate(restTemplate.getRequestFactory());
         this.baseURL = baseURL;
         this.restTemplate.getInterceptors().add((request, bytes, execution) -> {
             HttpRequest wrapper = new HttpRequestWrapper(request);
-            long calculatedTs = System.currentTimeMillis() + clientServerTimeDiff + AVG_REQUEST_TIMEOUT;
-            if (calculatedTs > mainTokenExpTs) {
-                synchronized (RestClient.this) {
-                    if (calculatedTs > mainTokenExpTs) {
-                        if (calculatedTs < refreshTokenExpTs) {
-                            refreshToken();
-                        } else {
-                            doLogin();
+            if (accessToken == null) {
+                long calculatedTs = System.currentTimeMillis() + clientServerTimeDiff + AVG_REQUEST_TIMEOUT;
+                if (calculatedTs > mainTokenExpTs) {
+                    synchronized (RestClient.this) {
+                        if (calculatedTs > mainTokenExpTs) {
+                            if (calculatedTs < refreshTokenExpTs) {
+                                refreshToken();
+                            } else {
+                                doLogin();
+                            }
                         }
                     }
                 }
+            } else {
+                mainToken = accessToken;
             }
             wrapper.getHeaders().set(JWT_TOKEN_HEADER_PARAM, "Bearer " + mainToken);
             return execution.execute(wrapper, bytes);
@@ -2403,7 +2415,7 @@ public class RestClient implements Closeable {
     }
 
     public Future<List<AttributeKvEntry>> getAttributeKvEntriesAsync(EntityId entityId, List<String> keys) {
-        return service.submit(() -> getAttributeKvEntries(entityId, keys));
+        return getExecutor().submit(() -> getAttributeKvEntries(entityId, keys));
     }
 
     public List<AttributeKvEntry> getAttributesByScope(EntityId entityId, String scope, List<String> keys) {
@@ -2976,7 +2988,7 @@ public class RestClient implements Closeable {
         addWidgetInfoFiltersToParams(tenantOnly, fullSearch, deprecatedFilter, widgetTypeList, params);
         return restTemplate.exchange(
                 baseURL + "/api/widgetTypes?" + getUrlParams(pageLink) +
-                        getWidgetTypeInfoPageRequestUrlParams(tenantOnly, fullSearch, deprecatedFilter, widgetTypeList),
+                getWidgetTypeInfoPageRequestUrlParams(tenantOnly, fullSearch, deprecatedFilter, widgetTypeList),
                 HttpMethod.GET,
                 HttpEntity.EMPTY,
                 new ParameterizedTypeReference<PageData<WidgetTypeInfo>>() {
@@ -3064,7 +3076,7 @@ public class RestClient implements Closeable {
         addWidgetInfoFiltersToParams(tenantOnly, fullSearch, deprecatedFilter, widgetTypeList, params);
         return restTemplate.exchange(
                 baseURL + "/api/widgetTypesInfos?widgetsBundleId={widgetsBundleId}&" + getUrlParams(pageLink) +
-                        getWidgetTypeInfoPageRequestUrlParams(tenantOnly, fullSearch, deprecatedFilter, widgetTypeList),
+                getWidgetTypeInfoPageRequestUrlParams(tenantOnly, fullSearch, deprecatedFilter, widgetTypeList),
                 HttpMethod.GET,
                 HttpEntity.EMPTY,
                 new ParameterizedTypeReference<PageData<WidgetTypeInfo>>() {
@@ -3765,7 +3777,7 @@ public class RestClient implements Closeable {
     }
 
     public PageData<TbResourceInfo> getImages(PageLink pageLink, boolean includeSystemImages) {
-       return this.getImages(pageLink, null, includeSystemImages);
+        return this.getImages(pageLink, null, includeSystemImages);
     }
 
     public PageData<TbResourceInfo> getImages(PageLink pageLink, ResourceSubType imageSubType, boolean includeSystemImages) {
@@ -4175,7 +4187,14 @@ public class RestClient implements Closeable {
 
     @Override
     public void close() {
-        service.shutdown();
+        if (executor.isInitialized()) {
+            getExecutor().shutdown();
+        }
+    }
+
+    @SneakyThrows
+    private ExecutorService getExecutor() {
+        return executor.get();
     }
 
 }