diff --git a/app/src/main/java/io/appium/uiautomator2/handler/GetSessionDetails.java b/app/src/main/java/io/appium/uiautomator2/handler/GetSessionDetails.java
index 230825694..ba5e4a2b6 100644
--- a/app/src/main/java/io/appium/uiautomator2/handler/GetSessionDetails.java
+++ b/app/src/main/java/io/appium/uiautomator2/handler/GetSessionDetails.java
@@ -1,3 +1,19 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package io.appium.uiautomator2.handler;
 
 import org.json.JSONException;
@@ -20,12 +36,12 @@ public GetSessionDetails(String mappedUri) {
     protected AppiumResponse safeHandle(IHttpRequest request) throws JSONException {
         Session session = AppiumUiAutomatorDriver.getInstance().getSession();
         JSONObject result = new JSONObject();
-        AccessibilityScrollData scrollData = session.getLastScrollData();
-        JSONObject lastScrollData = null;
-        if (scrollData != null) {
-            lastScrollData = new JSONObject(scrollData.getAsMap());
+        if (session != null) {
+            AccessibilityScrollData scrollData = session.getLastScrollData();
+            if (scrollData != null) {
+                result.put("lastScrollData", new JSONObject(scrollData.getAsMap()));
+            }
         }
-        result.put("lastScrollData", lastScrollData);
         return new AppiumResponse(getSessionId(request), WDStatus.SUCCESS, result);
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/io/appium/uiautomator2/handler/NewSession.java b/app/src/main/java/io/appium/uiautomator2/handler/NewSession.java
index dcd8d4ca8..640fdb298 100644
--- a/app/src/main/java/io/appium/uiautomator2/handler/NewSession.java
+++ b/app/src/main/java/io/appium/uiautomator2/handler/NewSession.java
@@ -1,5 +1,20 @@
-package io.appium.uiautomator2.handler;
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 
+package io.appium.uiautomator2.handler;
 
 import org.json.JSONException;
 
diff --git a/app/src/main/java/io/appium/uiautomator2/model/AppiumUiAutomatorDriver.java b/app/src/main/java/io/appium/uiautomator2/model/AppiumUiAutomatorDriver.java
index 76484c29a..db3254e72 100644
--- a/app/src/main/java/io/appium/uiautomator2/model/AppiumUiAutomatorDriver.java
+++ b/app/src/main/java/io/appium/uiautomator2/model/AppiumUiAutomatorDriver.java
@@ -1,8 +1,24 @@
-package io.appium.uiautomator2.model;
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 
+package io.appium.uiautomator2.model;
 
 import java.util.UUID;
 
+import androidx.annotation.Nullable;
 
 public class AppiumUiAutomatorDriver {
 
@@ -20,7 +36,6 @@ public static synchronized AppiumUiAutomatorDriver getInstance() {
     }
 
     public String initializeSession() {
-
         if (this.session != null) {
             session.getKnownElements().clear();
             return session.getSessionId();
@@ -29,6 +44,7 @@ public String initializeSession() {
         return session.getSessionId();
     }
 
+    @Nullable
     public Session getSession() {
         return session;
     }
diff --git a/app/src/main/java/io/appium/uiautomator2/model/Session.java b/app/src/main/java/io/appium/uiautomator2/model/Session.java
index fe2ed8bf0..4dc3fc708 100644
--- a/app/src/main/java/io/appium/uiautomator2/model/Session.java
+++ b/app/src/main/java/io/appium/uiautomator2/model/Session.java
@@ -8,6 +8,8 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 
+import androidx.annotation.Nullable;
+
 import static io.appium.uiautomator2.model.settings.Settings.ELEMENT_RESPONSE_ATTRIBUTES;
 import static io.appium.uiautomator2.model.settings.Settings.SHOULD_USE_COMPACT_RESPONSES;
 
@@ -63,6 +65,7 @@ public JSONObject getCommandConfiguration(String command) {
         return commandConfiguration.get(command);
     }
 
+    @Nullable
     public AccessibilityScrollData getLastScrollData() {
         return lastScrollData;
     }