diff --git a/app/src/main/java/com/owncloud/android/authentication/AuthenticatorAsyncTask.kt b/app/src/main/java/com/owncloud/android/authentication/AuthenticatorAsyncTask.kt
index e2f88f793296..0fc9025dd3fa 100644
--- a/app/src/main/java/com/owncloud/android/authentication/AuthenticatorAsyncTask.kt
+++ b/app/src/main/java/com/owncloud/android/authentication/AuthenticatorAsyncTask.kt
@@ -17,105 +17,97 @@
  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
-package com.owncloud.android.authentication;
-
-import android.app.Activity;
-import android.content.Context;
-import android.net.Uri;
-import android.os.AsyncTask;
-
-import com.nextcloud.common.NextcloudClient;
-import com.owncloud.android.lib.common.OwnCloudClient;
-import com.owncloud.android.lib.common.OwnCloudClientFactory;
-import com.owncloud.android.lib.common.OwnCloudCredentials;
-import com.owncloud.android.lib.common.UserInfo;
-import com.owncloud.android.lib.common.network.RedirectionPath;
-import com.owncloud.android.lib.common.operations.RemoteOperationResult;
-import com.owncloud.android.lib.resources.files.ExistenceCheckRemoteOperation;
-import com.owncloud.android.lib.resources.users.GetUserInfoRemoteOperation;
-
-import java.lang.ref.WeakReference;
-
-import static com.owncloud.android.datamodel.OCFile.ROOT_PATH;
-
+@file:Suppress("DEPRECATION")
+
+package com.owncloud.android.authentication
+
+import android.app.Activity
+import android.content.Context
+import android.net.Uri
+import android.os.AsyncTask
+import com.owncloud.android.datamodel.OCFile
+import com.owncloud.android.lib.common.OwnCloudClientFactory
+import com.owncloud.android.lib.common.OwnCloudCredentials
+import com.owncloud.android.lib.common.UserInfo
+import com.owncloud.android.lib.common.operations.RemoteOperationResult
+import com.owncloud.android.lib.resources.files.ExistenceCheckRemoteOperation
+import com.owncloud.android.lib.resources.users.GetUserInfoRemoteOperation
+import java.lang.ref.WeakReference
 
 /**
  * Async Task to verify the credentials of a user
  */
-public class AuthenticatorAsyncTask extends AsyncTask<Object, Void, RemoteOperationResult<UserInfo>> {
-
-    private static final boolean SUCCESS_IF_ABSENT = false;
 
-    private final WeakReference<Context> mWeakContext;
-    private final WeakReference<OnAuthenticatorTaskListener> mListener;
+class AuthenticatorAsyncTask(activity: Activity) : AsyncTask<Any?, Void?, RemoteOperationResult<UserInfo?>?>() {
+    private val mWeakContext: WeakReference<Context?>
+    private val mListener: WeakReference<OnAuthenticatorTaskListener>
 
-    public AuthenticatorAsyncTask(Activity activity) {
-        mWeakContext = new WeakReference<>(activity.getApplicationContext());
-        mListener = new WeakReference<>((OnAuthenticatorTaskListener) activity);
+    init {
+        mWeakContext = WeakReference(activity.applicationContext)
+        mListener = WeakReference(activity as OnAuthenticatorTaskListener)
     }
 
-    @Override
-    protected RemoteOperationResult<UserInfo> doInBackground(Object... params) {
+    @Deprecated("Deprecated in Java")
+    override fun doInBackground(vararg params: Any?): RemoteOperationResult<UserInfo?> {
+        val result: RemoteOperationResult<UserInfo?>
 
-        RemoteOperationResult<UserInfo> result;
-        if (params != null && params.length == 2 && mWeakContext.get() != null) {
-            String url = (String) params[0];
-            Context context = mWeakContext.get();
-            OwnCloudCredentials credentials = (OwnCloudCredentials) params[1];
+        if (params.size == 2 && mWeakContext.get() != null) {
+            val url = params[0] as String
+            val context = mWeakContext.get()
+            val credentials = params[1] as OwnCloudCredentials
 
             // Client
-            Uri uri = Uri.parse(url);
-            NextcloudClient nextcloudClient = OwnCloudClientFactory.createNextcloudClient(uri,
-                                                                                          credentials.getUsername(),
-                                                                                          credentials.toOkHttpCredentials(),
-                                                                                          context,
-                                                                                          true);
-
+            val uri = Uri.parse(url)
+            val nextcloudClient = OwnCloudClientFactory.createNextcloudClient(
+                uri,
+                credentials.username,
+                credentials.toOkHttpCredentials(),
+                context,
+                true
+            )
 
             // Operation - get display name
-            RemoteOperationResult<UserInfo> userInfoResult = new GetUserInfoRemoteOperation().execute(nextcloudClient);
+            val userInfoResult = GetUserInfoRemoteOperation().execute(nextcloudClient)
 
             // Operation - try credentials
-            if (userInfoResult.isSuccess()) {
-                OwnCloudClient client = OwnCloudClientFactory.createOwnCloudClient(uri, context, true);
-                client.setUserId(userInfoResult.getResultData().getId());
-                client.setCredentials(credentials);
-
-                ExistenceCheckRemoteOperation operation = new ExistenceCheckRemoteOperation(ROOT_PATH, SUCCESS_IF_ABSENT);
-                result = operation.execute(client);
-
+            if (userInfoResult.isSuccess) {
+                val client = OwnCloudClientFactory.createOwnCloudClient(uri, context, true)
+                client.userId = userInfoResult.resultData!!.id
+                client.credentials = credentials
+                val operation = ExistenceCheckRemoteOperation(OCFile.ROOT_PATH, SUCCESS_IF_ABSENT)
+                result = operation.execute(client) as RemoteOperationResult<UserInfo?>
                 if (operation.wasRedirected()) {
-                    RedirectionPath redirectionPath = operation.getRedirectionPath();
-                    String permanentLocation = redirectionPath.getLastPermanentLocation();
-                    result.setLastPermanentLocation(permanentLocation);
+                    val redirectionPath = operation.redirectionPath
+                    val permanentLocation = redirectionPath.lastPermanentLocation
+                    result.lastPermanentLocation = permanentLocation
                 }
-
-                result.setResultData(userInfoResult.getResultData());
+                result.setResultData(userInfoResult.resultData)
             } else {
-                result = userInfoResult;
+                result = userInfoResult
             }
         } else {
-            result = new RemoteOperationResult(RemoteOperationResult.ResultCode.UNKNOWN_ERROR);
+            result = RemoteOperationResult<UserInfo?>(RemoteOperationResult.ResultCode.UNKNOWN_ERROR)
         }
 
-        return result;
+        return result
     }
 
-    @Override
-    protected void onPostExecute(RemoteOperationResult<UserInfo> result) {
-
+    @Deprecated("Deprecated in Java")
+    override fun onPostExecute(result: RemoteOperationResult<UserInfo?>?) {
         if (result != null) {
-            OnAuthenticatorTaskListener listener = mListener.get();
-            if (listener != null) {
-                listener.onAuthenticatorTaskCallback(result);
-            }
+            val listener = mListener.get()
+            listener?.onAuthenticatorTaskCallback(result)
         }
     }
+
     /*
      * Interface to retrieve data from recognition task
      */
-    public interface OnAuthenticatorTaskListener{
+    interface OnAuthenticatorTaskListener {
+        fun onAuthenticatorTaskCallback(result: RemoteOperationResult<UserInfo?>?)
+    }
 
-        void onAuthenticatorTaskCallback(RemoteOperationResult<UserInfo> result);
+    companion object {
+        private const val SUCCESS_IF_ABSENT = false
     }
 }