Kotlin-Code is now compilable. Now let's go on to fix all those warning...

src/main/kotlin/de/fabianonline/telegram_backup/ApiStorage.kt

@@ -27,7 +27,7 @@ import java.io.File
 import java.io.FileNotFoundException
 import java.io.IOException
 
-internal class ApiStorage(prefix: String) : TelegramApiStorage {
+internal class ApiStorage(prefix: String?) : TelegramApiStorage {
     private var prefix: String? = null
     private var do_save = false
     private var auth_key: AuthKey? = null
@@ -39,7 +39,7 @@ internal class ApiStorage(prefix: String) : TelegramApiStorage {
         this.setPrefix(prefix)
     }
 
-    fun setPrefix(prefix: String) {
+    fun setPrefix(prefix: String?) {
         this.prefix = prefix
         this.do_save = this.prefix != null
         if (this.do_save) {
@@ -57,7 +57,7 @@ internal class ApiStorage(prefix: String) : TelegramApiStorage {
         }
     }
 
-    fun saveAuthKey(authKey: AuthKey) {
+    override fun saveAuthKey(authKey: AuthKey) {
         this.auth_key = authKey
         this._saveAuthKey()
     }
@@ -65,7 +65,7 @@ internal class ApiStorage(prefix: String) : TelegramApiStorage {
     private fun _saveAuthKey() {
         if (this.do_save && this.auth_key != null) {
             try {
-                FileUtils.writeByteArrayToFile(this.file_auth_key, this.auth_key!!.getKey())
+                FileUtils.writeByteArrayToFile(this.file_auth_key, this.auth_key!!.key)
             } catch (e: IOException) {
                 e.printStackTrace()
             }
@@ -73,7 +73,7 @@ internal class ApiStorage(prefix: String) : TelegramApiStorage {
         }
     }
 
-    fun loadAuthKey(): AuthKey? {
+    override fun loadAuthKey(): AuthKey? {
         if (this.auth_key != null) return this.auth_key
         if (this.file_auth_key != null) {
             try {
@@ -87,7 +87,7 @@ internal class ApiStorage(prefix: String) : TelegramApiStorage {
         return null
     }
 
-    fun saveDc(dc: DataCenter) {
+    override fun saveDc(dc: DataCenter) {
         this.dc = dc
         this._saveDc()
     }
@@ -103,7 +103,7 @@ internal class ApiStorage(prefix: String) : TelegramApiStorage {
         }
     }
 
-    fun loadDc(): DataCenter? {
+    override fun loadDc(): DataCenter? {
         if (this.dc != null) return this.dc
         if (this.file_dc != null) {
             try {
@@ -117,7 +117,7 @@ internal class ApiStorage(prefix: String) : TelegramApiStorage {
         return null
     }
 
-    fun deleteAuthKey() {
+    override fun deleteAuthKey() {
         if (this.do_save) {
             try {
                 FileUtils.forceDelete(this.file_auth_key)
@@ -128,7 +128,7 @@ internal class ApiStorage(prefix: String) : TelegramApiStorage {
         }
     }
 
-    fun deleteDc() {
+    override fun deleteDc() {
         if (this.do_save) {
             try {
                 FileUtils.forceDelete(this.file_dc)
@@ -139,9 +139,9 @@ internal class ApiStorage(prefix: String) : TelegramApiStorage {
         }
     }
 
-    fun saveSession(session: MTSession) {}
+    override fun saveSession(session: MTSession?) {}
 
-    fun loadSession(): MTSession? {
+    override fun loadSession(): MTSession? {
         return null
     }
 }

src/main/kotlin/de/fabianonline/telegram_backup/CommandLineController.kt

@@ -30,29 +30,24 @@ import org.slf4j.Logger
 class CommandLineController {
   private val storage:ApiStorage
   var app:TelegramApp
-  private val line:String
+  
-  get() {
+  private fun getLine():String {
-    if (System.console() != null)
+    if (System.console() != null) {
-    {
       return System.console().readLine("> ")
-    }
+    } else {
-    else
-    {
       print("> ")
       return Scanner(System.`in`).nextLine()
     }
   }
-  private val password:String
+  
-  get() {
+  private fun getPassword():String {
-    if (System.console() != null)
+    if (System.console() != null) {
-    {
       return String(System.console().readPassword("> "))
-    }
+    } else {
-    else
+      return getLine()
-    {
-      return line
     }
   }
+  
   init{
     logger.info("CommandLineController started. App version {}", Config.APP_APPVER)
     this.printHeader()
@@ -67,7 +62,7 @@ class CommandLineController {
     }
     else if (CommandLineOptions.cmd_license)
     {
-      this.show_license()
+      CommandLineController.show_license()
       System.exit(0)
     }
     this.setupFileBase()
@@ -92,16 +87,16 @@ class CommandLineController {
       logger.info("Initializing UserManager")
       UserManager.init(client)
       val user = UserManager.getInstance()
-      if (!CommandLineOptions.cmd_login && !user.isLoggedIn())
+      if (!CommandLineOptions.cmd_login && !user.loggedIn)
       {
         println("Your authorization data is invalid or missing. You will have to login with Telegram again.")
         CommandLineOptions.cmd_login = true
       }
-      if (account != null && user.isLoggedIn())
+      if (account != null && user.loggedIn)
       {
-        if (account != "+" + user.getUser().getPhone())
+        if (account != "+" + user.user!!.getPhone())
         {
-          logger.error("Account: {}, user.getUser().getPhone(): +{}", Utils.anonymize(account), Utils.anonymize(user.getUser().getPhone()))
+          logger.error("Account: {}, user.user!!.getPhone(): +{}", Utils.anonymize(account), Utils.anonymize(user.user!!.getPhone()))
           throw RuntimeException("Account / User mismatch")
         }
       }
@@ -137,7 +132,7 @@ class CommandLineController {
       logger.debug("CommandLineOptions.val_export: {}", CommandLineOptions.val_export)
       if (CommandLineOptions.val_export != null)
       {
-        if (CommandLineOptions.val_export.toLowerCase().equals("html"))
+        if (CommandLineOptions.val_export!!.toLowerCase().equals("html"))
         {
           (HTMLExporter()).export()
           System.exit(0)
@@ -147,9 +142,9 @@ class CommandLineController {
           show_error("Unknown export format.")
         }
       }
-      if (user.isLoggedIn())
+      if (user.loggedIn)
       {
-        System.out.println("You are logged in as " + Utils.anonymize(user.getUserString()))
+        System.out.println("You are logged in as " + Utils.anonymize(user.userString))
       }
       else
       {
@@ -202,13 +197,13 @@ class CommandLineController {
     logger.debug("Target dir at startup: {}", Utils.anonymize(Config.FILE_BASE))
     if (CommandLineOptions.val_target != null)
     {
-      Config.FILE_BASE = CommandLineOptions.val_target
+      Config.FILE_BASE = CommandLineOptions.val_target!!
     }
     logger.debug("Target dir after options: {}", Utils.anonymize(Config.FILE_BASE))
     System.out.println("Base directory for files: " + Utils.anonymize(Config.FILE_BASE))
   }
-  private fun selectAccount():String {
+  private fun selectAccount():String? {
-    val account:String = null
+    var account = "none"
     val accounts = Utils.getAccounts()
     if (CommandLineOptions.cmd_login)
     {
@@ -217,9 +212,9 @@ class CommandLineController {
     }
     else if (CommandLineOptions.val_account != null)
     {
-      logger.debug("Account requested: {}", Utils.anonymize(CommandLineOptions.val_account))
+      logger.debug("Account requested: {}", Utils.anonymize(CommandLineOptions.val_account!!))
       logger.trace("Checking accounts for match.")
-      val found = false
+      var found = false
       for (acc in accounts)
       {
         logger.trace("Checking {}", Utils.anonymize(acc))
@@ -232,16 +227,17 @@ class CommandLineController {
       }
       if (!found)
       {
-        show_error("Couldn't find account '" + Utils.anonymize(CommandLineOptions.val_account) + "'. Maybe you want to use '--login' first?")
+        show_error("Couldn't find account '" + Utils.anonymize(CommandLineOptions.val_account!!) + "'. Maybe you want to use '--login' first?")
       }
-      account = CommandLineOptions.val_account
+      account = CommandLineOptions.val_account!!
     }
-    else if (accounts.size() == 0)
+    else if (accounts.size == 0)
     {
       println("No accounts found. Starting login process...")
       CommandLineOptions.cmd_login = true
+      return null
     }
-    else if (accounts.size() == 1)
+    else if (accounts.size == 1)
     {
       account = accounts.firstElement()
       System.out.println("Using only available account: " + Utils.anonymize(account))
@@ -251,8 +247,9 @@ class CommandLineController {
       show_error(("You didn't specify which account to use.\n" +
                   "Use '--account <x>' to use account <x>.\n" +
                   "Use '--list-accounts' to see all available accounts."))
+	  System.exit(1)
     }
-    logger.debug("accounts.size(): {}", accounts.size())
+    logger.debug("accounts.size: {}", accounts.size)
     logger.debug("account: {}", Utils.anonymize(account))
     return account
   }
@@ -260,45 +257,48 @@ class CommandLineController {
     println()
     println("Stats:")
     val format = "%40s: %d%n"
-    System.out.format(format, "Number of accounts", Utils.getAccounts().size())
+    System.out.format(format, "Number of accounts", Utils.getAccounts().size)
     System.out.format(format, "Number of messages", Database.getInstance().getMessageCount())
     System.out.format(format, "Number of chats", Database.getInstance().getChatCount())
     System.out.format(format, "Number of users", Database.getInstance().getUserCount())
     System.out.format(format, "Top message ID", Database.getInstance().getTopMessageID())
     println()
     println("Media Types:")
-    for (pair in Database.getInstance().getMessageMediaTypesWithCount().entrySet())
+    for ((key, value) in Database.getInstance().getMessageMediaTypesWithCount())
     {
-      System.out.format(format, pair.key, pair.value)
+      System.out.format(format, key, value)
     }
     println()
     println("Api layers of messages:")
-    for (pair in Database.getInstance().getMessageApiLayerWithCount().entrySet())
+    for ((key, value) in Database.getInstance().getMessageApiLayerWithCount())
     {
-      System.out.format(format, pair.key, pair.value)
+      System.out.format(format, key, value)
     }
   }
   @Throws(RpcErrorException::class, IOException::class)
-  private fun cmd_login(phone:String) {
+  private fun cmd_login(phoneToUse:String?) {
     val user = UserManager.getInstance()
-    if (phone == null)
+    val phone: String
+    if (phoneToUse == null)
     {
       println("Please enter your phone number in international format.")
       println("Example: +4917077651234")
-      phone = line
+      phone = getLine()
+    } else {
+    	phone = phoneToUse
 	}
     user.sendCodeToPhoneNumber(phone)
     println("Telegram sent you a code. Please enter it here.")
-    val code = line
+    val code = getLine()
     user.verifyCode(code)
-    if (user.isPasswordNeeded())
+    if (user.isPasswordNeeded)
     {
       println("We also need your account password. Please enter it now. It should not be printed, so it's okay if you see nothing while typing it.")
-      val pw = password
+      val pw = getPassword()
       user.verifyPassword(pw)
     }
-    storage.setPrefix("+" + user.getUser().getPhone())
+    storage.setPrefix("+" + user.user!!.getPhone())
-    System.out.println("Everything seems fine. Please run this tool again with '--account +" + Utils.anonymize(user.getUser().getPhone()) + " to use this account.")
+    System.out.println("Everything seems fine. Please run this tool again with '--account +" + Utils.anonymize(user.user!!.getPhone()) + " to use this account.")
   }
   private fun show_help() {
     println("Valid options are:")
@@ -340,14 +340,14 @@ class CommandLineController {
   }
   companion object {
     private val logger = LoggerFactory.getLogger(CommandLineController::class.java)
-    fun show_error(error:String) {
+  
+  public fun show_error(error:String) {
     logger.error(error)
     println("ERROR: " + error)
     System.exit(1)
   }
   fun show_license() {
     println("TODO: Print the GPL.")
-        
   }
 }
 }

src/main/kotlin/de/fabianonline/telegram_backup/CommandLineDownloadProgress.kt

@@ -23,7 +23,7 @@ internal class CommandLineDownloadProgress : DownloadProgressInterface {
     private var mediaCount = 0
     private var i = 0
 
-    fun onMessageDownloadStart(count: Int, source: String?) {
+    override fun onMessageDownloadStart(count: Int, source: String?) {
         i = 0
         if (source == null) {
             System.out.println("Downloading $count messages.")
@@ -32,56 +32,56 @@ internal class CommandLineDownloadProgress : DownloadProgressInterface {
         }
     }
 
-    fun onMessageDownloaded(number: Int) {
+    override fun onMessageDownloaded(number: Int) {
         i += number
-        System.out.print("..." + i)
+        print("..." + i)
     }
 
-    fun onMessageDownloadFinished() {
+    override fun onMessageDownloadFinished() {
-        System.out.println(" done.")
+        println(" done.")
     }
 
-    fun onMediaDownloadStart(count: Int) {
+    override fun onMediaDownloadStart(count: Int) {
         i = 0
         mediaCount = count
-        System.out.println("Checking and downloading media.")
+        println("Checking and downloading media.")
-        System.out.println("Legend:")
+        println("Legend:")
-        System.out.println("'V' - Video         'P' - Photo         'D' - Document")
+        println("'V' - Video         'P' - Photo         'D' - Document")
-        System.out.println("'S' - Sticker       'A' - Audio         'G' - Geolocation")
+        println("'S' - Sticker       'A' - Audio         'G' - Geolocation")
-        System.out.println("'.' - Previously downloaded file        'e' - Empty file")
+        println("'.' - Previously downloaded file        'e' - Empty file")
-        System.out.println("' ' - Ignored media type (weblinks or contacts, for example)")
+        println("' ' - Ignored media type (weblinks or contacts, for example)")
-        System.out.println("'x' - File skipped because of timeout errors")
+        println("'x' - File skipped because of timeout errors")
-        System.out.println("" + count + " Files to check / download")
+        println("" + count + " Files to check / download")
     }
 
-    fun onMediaDownloaded(fm: AbstractMediaFileManager) {
+    override fun onMediaDownloaded(fm: AbstractMediaFileManager) {
-        show(fm.getLetter().toUpperCase())
+        show(fm.letter.toUpperCase())
     }
 
-    fun onMediaDownloadedEmpty() {
+    override fun onMediaDownloadedEmpty() {
         show("e")
     }
 
-    fun onMediaAlreadyPresent(fm: AbstractMediaFileManager) {
+    override fun onMediaAlreadyPresent(fm: AbstractMediaFileManager) {
         show(".")
     }
 
-    fun onMediaSkipped() {
+    override fun onMediaSkipped() {
         show("x")
     }
 
-    fun onMediaDownloadFinished() {
+    override fun onMediaDownloadFinished() {
         showNewLine()
-        System.out.println("Done.")
+        println("Done.")
     }
 
     private fun show(letter: String) {
-        System.out.print(letter)
+        print(letter)
         i++
         if (i % 100 == 0) showNewLine()
     }
 
     private fun showNewLine() {
-        System.out.println(" - $i/$mediaCount")
+        println(" - $i/$mediaCount")
     }
 }

src/main/kotlin/de/fabianonline/telegram_backup/CommandLineOptions.kt

@@ -92,7 +92,7 @@ internal object CommandLineOptions {
     }
     if (last_cmd != null)
     {
-      CommandLineController.show_error("Command " + last_cmd + " had no parameter set.")
+      CommandLineController.show_error("Command $last_cmd had no parameter set.")
     }
   }
 }

src/main/kotlin/de/fabianonline/telegram_backup/Config.kt

@@ -37,12 +37,12 @@ object Config {
     val FILE_FILES_BASE = "files"
     val FILE_STICKER_BASE = "stickers"
 
-    var DELAY_AFTER_GET_MESSAGES = 400
+    var DELAY_AFTER_GET_MESSAGES: Long = 400
-    var DELAY_AFTER_GET_FILE = 100
+    var DELAY_AFTER_GET_FILE: Long = 100
     var GET_MESSAGES_BATCH_SIZE = 200
 
     var RENAMING_MAX_TRIES = 5
-    var RENAMING_DELAY = 1000
+    var RENAMING_DELAY: Long = 1000
 
     val SECRET_GMAPS = "AIzaSyBEtUDhCQKEH6i2Mn1GAiQ9M_tLN0vxHIs"
 

src/main/kotlin/de/fabianonline/telegram_backup/Database.kt

@@ -52,8 +52,7 @@ class Database private constructor(var client: TelegramClient) {
     private var stmt: Statement? = null
     var user_manager: UserManager
 
-    val topMessageID: Int
+    fun getTopMessageID(): Int {
-        get() {
             try {
                 val rs = stmt!!.executeQuery("SELECT MAX(message_id) FROM messages WHERE source_type IN ('group', 'dialog')")
                 rs.next()
@@ -64,18 +63,15 @@ class Database private constructor(var client: TelegramClient) {
 
         }
 
-    val messageCount: Int
+    fun getMessageCount(): Int = queryInt("SELECT COUNT(*) FROM messages")
-        get() = queryInt("SELECT COUNT(*) FROM messages")
+    fun getChatCount(): Int = queryInt("SELECT COUNT(*) FROM chats")
-    val chatCount: Int
+    fun getUserCount(): Int = queryInt("SELECT COUNT(*) FROM users")
-        get() = queryInt("SELECT COUNT(*) FROM chats")
-    val userCount: Int
-        get() = queryInt("SELECT COUNT(*) FROM users")
 
-    val missingIDs: LinkedList<Integer>
+    val missingIDs: LinkedList<Int>
         get() {
             try {
-                val missing = LinkedList<Integer>()
+                val missing = LinkedList<Int>()
-                val max = topMessageID
+                val max = getTopMessageID()
                 val rs = stmt!!.executeQuery("SELECT message_id FROM messages WHERE source_type IN ('group', 'dialog') ORDER BY id")
                 rs.next()
                 var id = rs.getInt(1)
@@ -99,10 +95,9 @@ class Database private constructor(var client: TelegramClient) {
 
         }
 
-    val messagesWithMedia: LinkedList<TLMessage>
+    fun getMessagesWithMedia(): LinkedList<TLMessage?> {
-        get() {
             try {
-                val list = LinkedList<TLMessage>()
+                val list = LinkedList<TLMessage?>()
                 val rs = stmt!!.executeQuery("SELECT data FROM messages WHERE has_media=1")
                 while (rs.next()) {
                     list.add(bytesToTLMessage(rs.getBytes(1)))
@@ -116,10 +111,9 @@ class Database private constructor(var client: TelegramClient) {
 
         }
 
-    val messagesFromUserCount: Int
+    fun getMessagesFromUserCount(): Int {
-        get() {
             try {
-                val rs = stmt!!.executeQuery("SELECT COUNT(*) FROM messages WHERE sender_id=" + user_manager.getUser().getId())
+                val rs = stmt!!.executeQuery("SELECT COUNT(*) FROM messages WHERE sender_id=" + user_manager.user!!.getId())
                 rs.next()
                 return rs.getInt(1)
             } catch (e: SQLException) {
@@ -128,15 +122,12 @@ class Database private constructor(var client: TelegramClient) {
 
         }
 
-    val messageTypesWithCount: HashMap<String, Integer>
+    fun getMessageTypesWithCount(): HashMap<String, Int> = getMessageTypesWithCount(GlobalChat())
-        get() = getMessageTypesWithCount(GlobalChat())
 
-    val messageMediaTypesWithCount: HashMap<String, Integer>
+    fun getMessageMediaTypesWithCount(): HashMap<String, Int> = getMessageMediaTypesWithCount(GlobalChat())
-        get() = getMessageMediaTypesWithCount(GlobalChat())
 
-    val messageApiLayerWithCount: HashMap<String, Integer>
+    fun getMessageApiLayerWithCount(): HashMap<String, Int> {
-        get() {
+            val map = HashMap<String, Int>()
-            val map = HashMap<String, Integer>()
             try {
                 val rs = stmt!!.executeQuery("SELECT COUNT(id), api_layer FROM messages GROUP BY api_layer ORDER BY api_layer")
                 while (rs.next()) {
@@ -149,17 +140,13 @@ class Database private constructor(var client: TelegramClient) {
             } catch (e: Exception) {
                 throw RuntimeException(e)
             }
-
         }
 
-    val messageAuthorsWithCount: HashMap<String, Object>
+    fun getMessageAuthorsWithCount(): HashMap<String, Any> = getMessageAuthorsWithCount(GlobalChat())
-        get() = getMessageAuthorsWithCount(GlobalChat())
 
-    val messageTimesMatrix: Array<IntArray>
+    fun getMessageTimesMatrix(): Array<IntArray> = getMessageTimesMatrix(GlobalChat())
-        get() = getMessageTimesMatrix(GlobalChat())
 
-    val encoding: String
+    fun getEncoding(): String {
-        get() {
             try {
                 val rs = stmt!!.executeQuery("PRAGMA encoding")
                 rs.next()
@@ -172,8 +159,7 @@ class Database private constructor(var client: TelegramClient) {
         }
 
 
-    val listOfChatsForExport: LinkedList<Chat>
+    fun getListOfChatsForExport(): LinkedList<Chat> {
-        get() {
             val list = LinkedList<Chat>()
             try {
                 val rs = stmt!!.executeQuery("SELECT chats.id, chats.name, COUNT(messages.id) as c " +
@@ -192,8 +178,7 @@ class Database private constructor(var client: TelegramClient) {
         }
 
 
-    val listOfDialogsForExport: LinkedList<Dialog>
+    fun getListOfDialogsForExport(): LinkedList<Dialog> {
-        get() {
             val list = LinkedList<Dialog>()
             try {
                 val rs = stmt!!.executeQuery(
@@ -221,9 +206,7 @@ class Database private constructor(var client: TelegramClient) {
             CommandLineController.show_error("Could not load jdbc-sqlite class.")
         }
 
-        val path = "jdbc:sqlite:" +
+        val path = "jdbc:sqlite:${user_manager.fileBase}${Config.FILE_NAME_DB}"
-                user_manager.getFileBase() +
-                Config.FILE_NAME_DB
 
         try {
             conn = DriverManager.getConnection(path)
@@ -233,7 +216,7 @@ class Database private constructor(var client: TelegramClient) {
         }
 
         // Run updates
-        val updates = DatabaseUpdates(conn, this)
+        val updates = DatabaseUpdates(conn!!, this)
         updates.doUpdates()
 
         System.out.println("Database is ready.")
@@ -243,8 +226,8 @@ class Database private constructor(var client: TelegramClient) {
         val filename = String.format(Config.FILE_NAME_DB_BACKUP, currentVersion)
         System.out.println("  Creating a backup of your database as " + filename)
         try {
-            val src = user_manager.getFileBase() + Config.FILE_NAME_DB
+            val src = user_manager.fileBase + Config.FILE_NAME_DB
-            val dst = user_manager.getFileBase() + filename
+            val dst = user_manager.fileBase + filename
             logger.debug("Copying {} to {}", src, dst)
             Files.copy(
                     File(src).toPath(),
@@ -289,7 +272,7 @@ class Database private constructor(var client: TelegramClient) {
     }
 
     @Synchronized
-    fun saveMessages(all: TLVector<TLAbsMessage>, api_layer: Integer) {
+    fun saveMessages(all: TLVector<TLAbsMessage>, api_layer: Int) {
         try {
             //"(id, dialog_id, from_id, from_type, text, time, has_media, data, sticker, type) " +
             //"VALUES " +
@@ -312,16 +295,16 @@ class Database private constructor(var client: TelegramClient) {
                         ps.setInt(4, (peer as TLPeerChat).getChatId())
                     } else if (peer is TLPeerUser) {
                         var id = (peer as TLPeerUser).getUserId()
-                        if (id == this.user_manager.getUser().getId()) {
+                        if (id == this.user_manager.user!!.getId()) {
                             id = msg.getFromId()
                         }
                         ps.setString(3, "dialog")
                         ps.setInt(4, id)
                     } else if (peer is TLPeerChannel) {
                         ps.setString(3, "channel")
-                        ps.setInt(4, (peer as TLPeerChannel).getChannelId())
+                        ps.setInt(4, peer.getChannelId())
                     } else {
-                        throw RuntimeException("Unexpected Peer type: " + peer.getClass().getName())
+                        throw RuntimeException("Unexpected Peer type: " + peer.javaClass)
                     }
 
                     if (peer is TLPeerChannel) {
@@ -355,9 +338,9 @@ class Database private constructor(var client: TelegramClient) {
                         ps.setNull(12, Types.INTEGER)
                     } else {
                         ps.setBoolean(9, true)
-                        ps.setString(10, f!!.getName())
+                        ps.setString(10, f.name)
-                        ps.setString(11, f!!.getTargetFilename())
+                        ps.setString(11, f.targetFilename)
-                        ps.setInt(12, f!!.getSize())
+                        ps.setInt(12, f.size)
                     }
                     val stream = ByteArrayOutputStream()
                     msg.serializeBody(stream)
@@ -397,7 +380,7 @@ class Database private constructor(var client: TelegramClient) {
                     ps_insert_or_ignore.setInt(14, api_layer)
                     ps_insert_or_ignore.addBatch()
                 } else {
-                    throw RuntimeException("Unexpected Message type: " + abs.getClass().getName())
+                    throw RuntimeException("Unexpected Message type: " + abs.javaClass)
                 }
             }
             conn!!.setAutoCommit(false)
@@ -452,7 +435,7 @@ class Database private constructor(var client: TelegramClient) {
                     ps_insert_or_replace.setString(3, "channel")
                     ps_insert_or_replace.addBatch()
                 } else {
-                    throw RuntimeException("Unexpected " + abs.getClass().getName())
+                    throw RuntimeException("Unexpected " + abs.javaClass)
                 }
             }
             conn!!.setAutoCommit(false)
@@ -501,7 +484,7 @@ class Database private constructor(var client: TelegramClient) {
                     ps_insert_or_ignore.setNull(6, Types.VARCHAR)
                     ps_insert_or_ignore.addBatch()
                 } else {
-                    throw RuntimeException("Unexpected " + abs.getClass().getName())
+                    throw RuntimeException("Unexpected " + abs.javaClass)
                 }
             }
             conn!!.setAutoCommit(false)
@@ -518,9 +501,9 @@ class Database private constructor(var client: TelegramClient) {
 
     }
 
-    fun getIdsFromQuery(query: String): LinkedList<Integer> {
+    fun getIdsFromQuery(query: String): LinkedList<Int> {
         try {
-            val list = LinkedList<Integer>()
+            val list = LinkedList<Int>()
             val rs = stmt!!.executeQuery(query)
             while (rs.next()) {
                 list.add(rs.getInt(1))
@@ -533,8 +516,8 @@ class Database private constructor(var client: TelegramClient) {
 
     }
 
-    fun getMessageTypesWithCount(c: AbstractChat): HashMap<String, Integer> {
+    fun getMessageTypesWithCount(c: AbstractChat): HashMap<String, Int> {
-        val map = HashMap<String, Integer>()
+        val map = HashMap<String, Int>()
         try {
             val rs = stmt!!.executeQuery("SELECT message_type, COUNT(message_id) FROM messages WHERE " + c.query + " GROUP BY message_type")
             while (rs.next()) {
@@ -547,8 +530,8 @@ class Database private constructor(var client: TelegramClient) {
 
     }
 
-    fun getMessageMediaTypesWithCount(c: AbstractChat): HashMap<String, Integer> {
+    fun getMessageMediaTypesWithCount(c: AbstractChat): HashMap<String, Int> {
-        val map = HashMap<String, Integer>()
+        val map = HashMap<String, Int>()
         try {
             var count = 0
             val rs = stmt!!.executeQuery("SELECT media_type, COUNT(message_id) FROM messages WHERE " + c.query + " GROUP BY media_type")
@@ -569,9 +552,9 @@ class Database private constructor(var client: TelegramClient) {
 
     }
 
-    fun getMessageAuthorsWithCount(c: AbstractChat): HashMap<String, Object> {
+    fun getMessageAuthorsWithCount(c: AbstractChat): HashMap<String, Any> {
-        val map = HashMap<String, Object>()
+        val map = HashMap<String, Any>()
-        val user_map = HashMap<User, Integer>()
+        val user_map = HashMap<User, Int>()
         var count_others = 0
         // Set a default value for 'me' to fix the charts for channels - cause I
         // possibly didn't send any messages there.
@@ -596,7 +579,7 @@ class Database private constructor(var client: TelegramClient) {
                 }
             }
             map.put("authors.count.others", count_others)
-            map.put("authors.all", user_map.entrySet())
+            map.put("authors.all", user_map)
             return map
         } catch (e: Exception) {
             throw RuntimeException(e)
@@ -621,7 +604,7 @@ class Database private constructor(var client: TelegramClient) {
 
     }
 
-    fun getMessagesForExport(c: AbstractChat): LinkedList<HashMap<String, Object>> {
+    fun getMessagesForExport(c: AbstractChat): LinkedList<HashMap<String, Any>> {
         try {
 
             val rs = stmt!!.executeQuery("SELECT messages.message_id as message_id, text, time*1000 as time, has_media, " +
@@ -637,13 +620,13 @@ class Database private constructor(var client: TelegramClient) {
             val format_date = SimpleDateFormat("d MMM yy")
             val meta = rs.getMetaData()
             val columns = meta.getColumnCount()
-            val list = LinkedList<HashMap<String, Object>>()
+            val list = LinkedList<HashMap<String, Any>>()
 
-            var count: Integer = 0
+            var count = 0
             var old_date: String? = null
-            var old_user: Integer? = null
+            var old_user = 0
             while (rs.next()) {
-                val h = HashMap<String, Object>(columns)
+                val h = HashMap<String, Any>(columns)
                 for (i in 1..columns) {
                     h.put(meta.getColumnName(i), rs.getObject(i))
                 }
@@ -655,7 +638,7 @@ class Database private constructor(var client: TelegramClient) {
                 if (rs.getString("media_type") != null) {
                     h.put("media_" + rs.getString("media_type"), true)
                 }
-                h.put("from_me", rs.getInt("user_id") === user_manager.getUser().getId())
+                h.put("from_me", rs.getInt("user_id") === user_manager.user!!.getId())
                 h.put("is_new_date", !date.equals(old_date))
                 h.put("odd_even", if (count % 2 == 0) "even" else "odd")
                 h.put("same_user", old_user != null && rs.getInt("user_id") === old_user)
@@ -696,7 +679,7 @@ class Database private constructor(var client: TelegramClient) {
         var isMe: Boolean = false
 
         init {
-            isMe = id == user_manager.getUser().getId()
+            isMe = id == user_manager.user!!.getId()
             val s = StringBuilder()
             if (first_name != null) s.append(first_name + " ")
             if (last_name != null) s.append(last_name)
@@ -711,7 +694,7 @@ class Database private constructor(var client: TelegramClient) {
 
     companion object {
         private val logger = LoggerFactory.getLogger(Database::class.java)
-        private var instance: Database? = null
+        internal var instance: Database? = null
 
         fun init(c: TelegramClient) {
             instance = Database(c)
@@ -719,7 +702,7 @@ class Database private constructor(var client: TelegramClient) {
 
         fun getInstance(): Database {
             if (instance == null) throw RuntimeException("Database is not initialized but getInstance() was called.")
-            return instance
+            return instance!!
         }
 
         fun bytesToTLMessage(b: ByteArray?): TLMessage? {

src/main/kotlin/de/fabianonline/telegram_backup/DatabaseUpdates.kt

@@ -18,7 +18,7 @@ import de.fabianonline.telegram_backup.mediafilemanager.AbstractMediaFileManager
 class DatabaseUpdates(protected var conn: Connection, protected var db: Database) {
 
     private val maxPossibleVersion: Int
-        get() = updates.size()
+        get() = updates.size
 
     init {
         logger.debug("Registering Database Updates...")
@@ -62,7 +62,7 @@ class DatabaseUpdates(protected var conn: Connection, protected var db: Database
                 logger.debug("Update is necessary. {} => {}.", version, maxPossibleVersion)
                 var backup = false
                 for (i in version + 1..maxPossibleVersion) {
-                    if (getUpdateToVersion(i).needsBackup()) {
+                    if (getUpdateToVersion(i).needsBackup) {
                         logger.debug("Update to version {} needs a backup", i)
                         backup = true
                     }
@@ -100,9 +100,9 @@ class DatabaseUpdates(protected var conn: Connection, protected var db: Database
     }
 
     private fun register(d: DatabaseUpdate) {
-        logger.debug("Registering {} as update to version {}", d.getClass().getName(), d.version)
+        logger.debug("Registering {} as update to version {}", d.javaClass, d.version)
-        if (d.version != updates.size() + 1) {
+        if (d.version != updates.size + 1) {
-            throw RuntimeException("Tried to register DB update to version " + d.version + ", but would need update to version " + (updates.size() + 1))
+            throw RuntimeException("Tried to register DB update to version ${d.version}, but would need update to version ${updates.size + 1}")
         }
         updates.add(d)
     }
@@ -138,9 +138,7 @@ internal abstract class DatabaseUpdate(protected var conn: Connection, protected
     @Throws(SQLException::class)
     protected abstract fun _doUpdate()
 
-    fun needsBackup(): Boolean {
+    open val needsBackup = false
-        return false
-    }
 
     @Throws(SQLException::class)
     protected fun execute(sql: String) {
@@ -233,9 +231,7 @@ internal class DB_Update_6(conn: Connection, db: Database) : DatabaseUpdate(conn
     override val version: Int
         get() = 6
 
-    override fun needsBackup(): Boolean {
+    override val needsBackup = true
-        return true
-    }
 
     @Throws(SQLException::class)
     override fun _doUpdate() {
@@ -269,14 +265,14 @@ internal class DB_Update_6(conn: Connection, db: Database) : DatabaseUpdate(conn
         val query = StringBuilder("INSERT INTO messages_new\n(")
         var first: Boolean
         first = true
-        for (s in mappings.keySet()) {
+        for (s in mappings.keys) {
             if (!first) query.append(", ")
             query.append(s)
             first = false
         }
         query.append(")\nSELECT \n")
         first = true
-        for (s in mappings.values()) {
+        for (s in mappings.values) {
             if (!first) query.append(", ")
             query.append(s)
             first = false
@@ -289,7 +285,7 @@ internal class DB_Update_6(conn: Connection, db: Database) : DatabaseUpdate(conn
         val ps = conn.prepareStatement("UPDATE messages_new SET fwd_from_id=?, media_type=?, media_file=?, media_size=? WHERE id=?")
         while (rs.next()) {
             ps.setInt(5, rs.getInt(1))
-            val msg = db.bytesToTLMessage(rs.getBytes(2))
+            val msg = Database.bytesToTLMessage(rs.getBytes(2))
             if (msg == null || msg!!.getFwdFrom() == null) {
                 ps.setNull(1, Types.INTEGER)
             } else {
@@ -301,9 +297,9 @@ internal class DB_Update_6(conn: Connection, db: Database) : DatabaseUpdate(conn
                 ps.setNull(3, Types.VARCHAR)
                 ps.setNull(4, Types.INTEGER)
             } else {
-                ps.setString(2, f!!.getName())
+                ps.setString(2, f.name)
-                ps.setString(3, f!!.getTargetFilename())
+                ps.setString(3, f.targetFilename)
-                ps.setInt(4, f!!.getSize())
+                ps.setInt(4, f.size)
             }
             ps.addBatch()
         }
@@ -321,9 +317,7 @@ internal class DB_Update_7(conn: Connection, db: Database) : DatabaseUpdate(conn
     override val version: Int
         get() = 7
 
-    override fun needsBackup(): Boolean {
+    override val needsBackup = true
-        return true
-    }
 
     @Throws(SQLException::class)
     override fun _doUpdate() {
@@ -337,9 +331,7 @@ internal class DB_Update_8(conn: Connection, db: Database) : DatabaseUpdate(conn
     override val version: Int
         get() = 8
 
-    override fun needsBackup(): Boolean {
+    override val needsBackup = true
-        return true
-    }
 
     @Throws(SQLException::class)
     override fun _doUpdate() {

src/main/kotlin/de/fabianonline/telegram_backup/DownloadManager.kt

@@ -65,7 +65,7 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
     }
 
     @Throws(RpcErrorException::class, IOException::class)
-    fun downloadMessages(limit: Integer) {
+    fun downloadMessages(limit: Int?) {
         var completed = true
         do {
             completed = true
@@ -95,7 +95,7 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
     }
 
     @Throws(RpcErrorException::class, IOException::class, TimeoutException::class)
-    fun _downloadMessages(limit: Integer?) {
+    fun _downloadMessages(limit: Int?) {
         logger.info("This is _downloadMessages with limit {}", limit)
         val dialog_limit = 100
         logger.info("Downloading the last {} dialogs", dialog_limit)
@@ -106,11 +106,11 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
                 0,
                 TLInputPeerEmpty(),
                 dialog_limit)
-        logger.debug("Got {} dialogs", dialogs.getDialogs().size())
+        logger.debug("Got {} dialogs", dialogs.getDialogs().size)
 
         for (d in dialogs.getDialogs()) {
             if (d.getTopMessage() > max_message_id && d.getPeer() !is TLPeerChannel) {
-                logger.trace("Updating top message id: {} => {}. Dialog type: {}", max_message_id, d.getTopMessage(), d.getPeer().getClass().getName())
+                logger.trace("Updating top message id: {} => {}. Dialog type: {}", max_message_id, d.getTopMessage(), d.getPeer().javaClass)
                 max_message_id = d.getTopMessage()
             }
         }
@@ -174,10 +174,10 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
             System.out.println("Processing channels and/or supergroups...")
             System.out.println("Please note that only channels/supergroups in the last 100 active chats are processed.")
 
-            val channel_access_hashes = HashMap<Integer, Long>()
+            val channel_access_hashes = HashMap<Int, Long>()
-            val channel_names = HashMap<Integer, String>()
+            val channel_names = HashMap<Int, String>()
-            val channels = LinkedList<Integer>()
+            val channels = LinkedList<Int>()
-            val supergroups = LinkedList<Integer>()
+            val supergroups = LinkedList<Int>()
 
             // TODO Add chat title (and other stuff?) to the database
             for (c in dialogs.getChats()) {
@@ -224,21 +224,21 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
     }
 
     @Throws(RpcErrorException::class, IOException::class)
-    private fun downloadMessages(ids: List<Integer>, channel: TLInputChannel?, source_string: String?) {
+    private fun downloadMessages(ids: MutableList<Int>, channel: TLInputChannel?, source_string: String?) {
-        prog!!.onMessageDownloadStart(ids.size(), source_string)
+        prog!!.onMessageDownloadStart(ids.size, source_string)
 
         logger.debug("Entering download loop")
-        while (ids.size() > 0) {
+        while (ids.size > 0) {
             logger.trace("Loop")
             val vector = TLIntVector()
             val download_count = Config.GET_MESSAGES_BATCH_SIZE
             logger.trace("download_count: {}", download_count)
             for (i in 0 until download_count) {
-                if (ids.size() === 0) break
+                if (ids.size === 0) break
-                vector.add(ids.remove(0))
+                vector.add(ids.removeAt(0))
             }
-            logger.trace("vector.size(): {}", vector.size())
+            logger.trace("vector.size(): {}", vector.size)
-            logger.trace("ids.size(): {}", ids.size())
+            logger.trace("ids.size(): {}", ids.size)
 
             var response: TLAbsMessages
             var tries = 0
@@ -265,12 +265,12 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
                 }
 
             }
-            logger.trace("response.getMessages().size(): {}", response.getMessages().size())
+            logger.trace("response.getMessages().size(): {}", response.getMessages().size)
-            if (response.getMessages().size() !== vector.size()) {
+            if (response.getMessages().size !== vector.size) {
-                CommandLineController.show_error("Requested " + vector.size() + " messages, but got " + response.getMessages().size() + ". That is unexpected. Quitting.")
+                CommandLineController.show_error("Requested ${vector.size} messages, but got ${response.getMessages().size}. That is unexpected. Quitting.")
             }
 
-            prog!!.onMessageDownloaded(response.getMessages().size())
+            prog!!.onMessageDownloaded(response.getMessages().size)
             db!!.saveMessages(response.getMessages(), Kotlogram.API_LAYER)
             db!!.saveChats(response.getChats())
             db!!.saveUsers(response.getUsers())
@@ -319,26 +319,27 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
         logger.info("This is _downloadMedia")
         logger.info("Checking if there are messages in the DB with a too old API layer")
         val ids = db!!.getIdsFromQuery("SELECT id FROM messages WHERE has_media=1 AND api_layer<" + Kotlogram.API_LAYER)
-        if (ids.size() > 0) {
+        if (ids.size > 0) {
-            System.out.println("You have " + ids.size() + " messages in your db that need an update. Doing that now.")
+            System.out.println("You have ${ids.size} messages in your db that need an update. Doing that now.")
-            logger.debug("Found {} messages", ids.size())
+            logger.debug("Found {} messages", ids.size)
             downloadMessages(ids, null, null)
         }
 
         val messages = this.db!!.getMessagesWithMedia()
-        logger.debug("Database returned {} messages with media", messages.size())
+        logger.debug("Database returned {} messages with media", messages.size)
-        prog!!.onMediaDownloadStart(messages.size())
+        prog!!.onMediaDownloadStart(messages.size)
         for (msg in messages) {
-            val m = FileManagerFactory.getFileManager(msg, user, client)
+        	if (msg==null) continue
+            val m = FileManagerFactory.getFileManager(msg, user!!, client!!)
             logger.trace("message {}, {}, {}, {}, {}",
                     msg.getId(),
-                    msg.getMedia().getClass().getSimpleName().replace("TLMessageMedia", "…"),
+                    msg.getMedia().javaClass.getSimpleName().replace("TLMessageMedia", "…"),
-                    m.getClass().getSimpleName(),
+                    m!!.javaClass.getSimpleName(),
-                    if (m.isEmpty()) "empty" else "non-empty",
+                    if (m.isEmpty) "empty" else "non-empty",
-                    if (m.isDownloaded()) "downloaded" else "not downloaded")
+                    if (m.downloaded) "downloaded" else "not downloaded")
-            if (m.isEmpty()) {
+            if (m.isEmpty) {
                 prog!!.onMediaDownloadedEmpty()
-            } else if (m.isDownloaded()) {
+            } else if (m.downloaded) {
                 prog!!.onMediaAlreadyPresent(m)
             } else {
                 try {
@@ -354,8 +355,8 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
         prog!!.onMediaDownloadFinished()
     }
 
-    private fun makeIdList(start: Int, end: Int): List<Integer> {
+    private fun makeIdList(start: Int, end: Int): MutableList<Int> {
-        val a = LinkedList<Integer>()
+        val a = LinkedList<Int>()
         for (i in start..end) a.add(i)
         return a
     }
@@ -378,7 +379,7 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
         }
 
         @Throws(RpcErrorException::class, IOException::class, TimeoutException::class)
-        private fun downloadFileFromDc(client: TelegramClient, target: String, loc: TLAbsInputFileLocation, dcID: Integer?, size: Int): Boolean {
+        private fun downloadFileFromDc(client: TelegramClient, target: String, loc: TLAbsInputFileLocation, dcID: Int, size: Int): Boolean {
             var fos: FileOutputStream? = null
             try {
                 val temp_filename = target + ".downloading"
@@ -388,7 +389,7 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
                 var offset = 0
                 if (File(temp_filename).isFile()) {
                     logger.info("Temporary filename already exists; continuing this file")
-                    offset = File(temp_filename).length()
+                    offset = File(temp_filename).length() as Int
                     if (offset >= size) {
                         logger.warn("Temporary file size is >= the target size. Assuming corrupt file & deleting it")
                         File(temp_filename).delete()
@@ -422,8 +423,8 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
                         }
                     }
 
-                    offset += response!!.getBytes().getData().length
+                    offset += response!!.getBytes().getData().size
-                    logger.trace("response: {} total size: {}", response!!.getBytes().getData().length, offset)
+                    logger.trace("response: {} total size: {}", response!!.getBytes().getData().size, offset)
 
                     fos!!.write(response!!.getBytes().getData())
                     fos!!.flush()
@@ -432,7 +433,7 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
                     } catch (e: InterruptedException) {
                     }
 
-                } while (offset < size && (response!!.getBytes().getData().length > 0 || try_again))
+                } while (offset < size && (response!!.getBytes().getData().size > 0 || try_again))
                 fos!!.close()
                 if (offset < size) {
                     System.out.println("Requested file $target with $size bytes, but got only $offset bytes.")

src/main/kotlin/de/fabianonline/telegram_backup/DownloadProgressInterface.kt

@@ -19,7 +19,7 @@ package de.fabianonline.telegram_backup
 import de.fabianonline.telegram_backup.mediafilemanager.AbstractMediaFileManager
 
 interface DownloadProgressInterface {
-    fun onMessageDownloadStart(count: Int, source: String)
+    fun onMessageDownloadStart(count: Int, source: String?)
     fun onMessageDownloaded(number: Int)
     fun onMessageDownloadFinished()
 

src/main/kotlin/de/fabianonline/telegram_backup/GUIController.kt

@@ -24,7 +24,7 @@ import java.awt.event.ActionEvent
 import java.awt.event.ActionListener
 import java.util.Vector
 
-class GUIController {
+class GUIController() {
     init {
         showAccountChooserDialog()
     }
@@ -50,22 +50,6 @@ class GUIController {
         accountChooser.add(vert)
         accountChooser.setVisible(true)
         accountChooser.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE)
-
-        list.addListSelectionListener(object : ListSelectionListener() {
-            @Override
-            fun valueChanged(e: ListSelectionEvent) {
-                btnLogin.setEnabled(true)
-            }
-        })
-
-        btnAddAccount.addActionListener(object : ActionListener() {
-            @Override
-            fun actionPerformed(e: ActionEvent) {
-                accountChooser.setVisible(false)
-                accountChooser.dispose()
-                addAccountDialog()
-            }
-        })
 	}
 	
     private fun addAccountDialog() {

src/main/kotlin/de/fabianonline/telegram_backup/TLRequestAccountGetPasswordWithCurrentSalt.kt

@@ -28,16 +28,15 @@ import com.github.badoualy.telegram.tl.StreamUtils.readTLObject
 
 class TLRequestAccountGetPasswordWithCurrentSalt : TLMethod<TLPassword>() {
     private val _constructor = "account.getPassword#548a30f5"
-    val constructorId: Int
+    override fun getConstructorId(): Int = CONSTRUCTOR_ID
-        get() = CONSTRUCTOR_ID
 
     @Throws(IOException::class)
-    fun deserializeResponse(stream: InputStream, context: TLContext): TLPassword {
+    override fun deserializeResponse(stream: InputStream, context: TLContext): TLPassword {
         val response = (readTLObject(stream, context) ?: throw IOException("Unable to parse response")) as? TLPassword ?: throw IOException("Incorrect response type, expected getClass().getCanonicalName(), found response.getClass().getCanonicalName()")
         return response as TLPassword
     }
 
-    fun toString(): String {
+    override fun toString(): String {
         return _constructor
     }
 

src/main/kotlin/de/fabianonline/telegram_backup/TelegramUpdateHandler.kt

@@ -37,18 +37,18 @@ internal class TelegramUpdateHandler : UpdateCallback {
         this.db = Database.getInstance()
     }
 
-    fun onUpdates(c: TelegramClient, u: TLUpdates) {
+    override fun onUpdates(c: TelegramClient, u: TLUpdates) {
         if (db == null) return
-        if (debug) System.out.println("onUpdates - " + u.getUpdates().size() + " Updates, " + u.getUsers().size() + " Users, " + u.getChats().size() + " Chats")
+        if (debug) System.out.println("onUpdates - " + u.getUpdates().size + " Updates, " + u.getUsers().size + " Users, " + u.getChats().size + " Chats")
         for (update in u.getUpdates()) {
             processUpdate(update, c)
-            if (debug) System.out.println("  " + update.getClass().getName())
+            if (debug) System.out.println("  " + update.javaClass.getName())
         }
         db!!.saveUsers(u.getUsers())
         db!!.saveChats(u.getChats())
     }
 
-    fun onUpdatesCombined(c: TelegramClient, u: TLUpdatesCombined) {
+    override fun onUpdatesCombined(c: TelegramClient, u: TLUpdatesCombined) {
         if (db == null) return
         if (debug) System.out.println("onUpdatesCombined")
         for (update in u.getUpdates()) {
@@ -58,14 +58,14 @@ internal class TelegramUpdateHandler : UpdateCallback {
         db!!.saveChats(u.getChats())
     }
 
-    fun onUpdateShort(c: TelegramClient, u: TLUpdateShort) {
+    override fun onUpdateShort(c: TelegramClient, u: TLUpdateShort) {
         if (db == null) return
         if (debug) System.out.println("onUpdateShort")
         processUpdate(u.getUpdate(), c)
-        if (debug) System.out.println("  " + u.getUpdate().getClass().getName())
+        if (debug) System.out.println("  " + u.getUpdate().javaClass.getName())
     }
 
-    fun onShortChatMessage(c: TelegramClient, m: TLUpdateShortChatMessage) {
+    override fun onShortChatMessage(c: TelegramClient, m: TLUpdateShortChatMessage) {
         if (db == null) return
         if (debug) System.out.println("onShortChatMessage - " + m.getMessage())
         val msg = TLMessage(
@@ -89,16 +89,16 @@ internal class TelegramUpdateHandler : UpdateCallback {
         System.out.print('.')
     }
 
-    fun onShortMessage(c: TelegramClient, m: TLUpdateShortMessage) {
+    override fun onShortMessage(c: TelegramClient, m: TLUpdateShortMessage) {
         if (db == null) return
         if (debug) System.out.println("onShortMessage - " + m.getOut() + " - " + m.getUserId() + " - " + m.getMessage())
         val from_id: Int
         val to_id: Int
         if (m.getOut() === true) {
-            from_id = user!!.getUser().getId()
+            from_id = user!!.user!!.getId()
             to_id = m.getUserId()
         } else {
-            to_id = user!!.getUser().getId()
+            to_id = user!!.user!!.getId()
             from_id = m.getUserId()
         }
         val msg = TLMessage(
@@ -122,12 +122,12 @@ internal class TelegramUpdateHandler : UpdateCallback {
         System.out.print('.')
     }
 
-    fun onShortSentMessage(c: TelegramClient, m: TLUpdateShortSentMessage) {
+    override fun onShortSentMessage(c: TelegramClient, m: TLUpdateShortSentMessage) {
         if (db == null) return
         System.out.println("onShortSentMessage")
     }
 
-    fun onUpdateTooLong(c: TelegramClient) {
+    override fun onUpdateTooLong(c: TelegramClient) {
         if (db == null) return
         System.out.println("onUpdateTooLong")
     }
@@ -140,8 +140,8 @@ internal class TelegramUpdateHandler : UpdateCallback {
             db!!.saveMessages(vector, Kotlogram.API_LAYER)
             System.out.print('.')
             if (abs_msg is TLMessage) {
-                val fm = FileManagerFactory.getFileManager(abs_msg as TLMessage, user, client)
+                val fm = FileManagerFactory.getFileManager(abs_msg as TLMessage, user!!, client)
-                if (fm != null && !fm!!.isEmpty() && !fm!!.isDownloaded()) {
+                if (fm != null && !fm!!.isEmpty && !fm!!.downloaded) {
                     try {
                         fm!!.download()
                     } catch (e: Exception) {

src/main/kotlin/de/fabianonline/telegram_backup/UserManager.kt

@@ -39,13 +39,13 @@ private constructor(c: TelegramClient) {
     var user: TLUser? = null
     var phone: String? = null
     private var code: String? = null
-    private val client: TelegramClient? = null
+    private val client: TelegramClient
     private var sent_code: TLSentCode? = null
     private var auth: TLAuthorization? = null
     var isPasswordNeeded = false
         private set
 
-    val isLoggedIn: Boolean
+    val loggedIn: Boolean
         get() = user != null
 
     val userString: String
@@ -86,7 +86,7 @@ private constructor(c: TelegramClient) {
     @Throws(RpcErrorException::class, IOException::class)
     fun sendCodeToPhoneNumber(number: String) {
         this.phone = number
-        this.sent_code = this.client!!.authSendCode(false, this.phone, true)
+        this.sent_code = this.client!!.authSendCode(false, number, true)
     }
 
     @Throws(RpcErrorException::class, IOException::class)
@@ -104,7 +104,7 @@ private constructor(c: TelegramClient) {
 
     @Throws(RpcErrorException::class, IOException::class)
     fun verifyPassword(pw: String) {
-        val password = pw.getBytes("UTF-8")
+        val password = pw.toByteArray(charset=Charsets.UTF_8)
         val salt = (client!!.accountGetPassword() as TLPassword).getCurrentSalt().getData()
         var md: MessageDigest? = null
         try {
@@ -125,7 +125,7 @@ private constructor(c: TelegramClient) {
 
     companion object {
         private val logger = LoggerFactory.getLogger(UserManager::class.java)
-        private var instance: UserManager? = null
+        internal var instance: UserManager? = null
 
         @Throws(IOException::class)
         fun init(c: TelegramClient) {
@@ -134,7 +134,7 @@ private constructor(c: TelegramClient) {
 
         fun getInstance(): UserManager {
             if (instance == null) throw RuntimeException("UserManager is not yet initialized.")
-            return instance
+            return instance!!
         }
     }
 }

src/main/kotlin/de/fabianonline/telegram_backup/Utils.kt

@@ -34,8 +34,7 @@ object Utils {
 
     private val logger = LoggerFactory.getLogger(Utils::class.java) as Logger
 
-    internal val accounts: Vector<String>
+    fun getAccounts(): Vector<String> {
-        get() {
             val accounts = Vector<String>()
             val folder = File(Config.FILE_BASE)
             val files = folder.listFiles()
@@ -48,8 +47,7 @@ object Utils {
             return accounts
         }
 
-    internal val newestVersion: Version?
+    fun getNewestVersion(): Version? {
-        get() {
             try {
                 val data_url = "https://api.github.com/repos/fabianonline/telegram_backup/releases"
                 logger.debug("Requesting current release info from {}", data_url)
@@ -87,7 +85,7 @@ object Utils {
     @JvmOverloads internal fun obeyFloodWaitException(e: RpcErrorException?, silent: Boolean = false) {
         if (e == null || e!!.getCode() !== 420) return
 
-        val delay = e!!.getTagInteger()
+        val delay: Long = e!!.getTagInteger()!! as Long
         if (!silent) {
             System.out.println("")
             System.out.println(
@@ -112,13 +110,13 @@ object Utils {
         logger.debug("Comparing versions {} and {}.", v1, v2)
         if (v1.equals(v2)) return VERSIONS_EQUAL
 
-        val v1_p = v1.split("-", 2)
+        val v1_p = v1.split("-", limit=2)
-        val v2_p = v2.split("-", 2)
+        val v2_p = v2.split("-", limit=2)
 
         logger.trace("Parts to compare without suffixes: {} and {}.", v1_p[0], v2_p[0])
 
-        val v1_p2 = v1_p[0].split("\\.")
+        val v1_p2 = v1_p[0].split(".")
-        val v2_p2 = v2_p[0].split("\\.")
+        val v2_p2 = v2_p[0].split(".")
 
         logger.trace("Length of the parts without suffixes: {} and {}.", v1_p2.size, v2_p2.size)
 
@@ -179,6 +177,6 @@ object Utils {
     }
 
     fun anonymize(str: String): String {
-        return if (!CommandLineOptions.cmd_anonymize) str else str.replaceAll("[0-9]", "1").replaceAll("[A-Z]", "A").replaceAll("[a-z]", "a") + " (ANONYMIZED)"
+        return if (!CommandLineOptions.cmd_anonymize) str else str.replace("[0-9]".toRegex(), "1").replace("[A-Z]".toRegex(), "A").replace("[a-z]".toRegex(), "a") + " (ANONYMIZED)"
     }
 }

src/main/kotlin/de/fabianonline/telegram_backup/exporter/HTMLExporter.kt

@@ -50,26 +50,26 @@ class HTMLExporter {
 
             // Create base dir
             logger.debug("Creating base dir")
-            val base = user.getFileBase() + "files" + File.separatorChar
+            val base = user.fileBase + "files" + File.separatorChar
             File(base).mkdirs()
             File(base + "dialogs").mkdirs()
 
             logger.debug("Fetching dialogs")
             val dialogs = db.getListOfDialogsForExport()
-            logger.trace("Got {} dialogs", dialogs.size())
+            logger.trace("Got {} dialogs", dialogs.size)
             logger.debug("Fetching chats")
             val chats = db.getListOfChatsForExport()
-            logger.trace("Got {} chats", chats.size())
+            logger.trace("Got {} chats", chats.size)
 
             logger.debug("Generating index.html")
-            val scope = HashMap<String, Object>()
+            val scope = HashMap<String, Any>()
             scope.put("user", user)
             scope.put("dialogs", dialogs)
             scope.put("chats", chats)
 
             // Collect stats data
-            scope.put("count.chats", chats.size())
+            scope.put("count.chats", chats.size)
-            scope.put("count.dialogs", dialogs.size())
+            scope.put("count.dialogs", dialogs.size)
 
             var count_messages_chats = 0
             var count_messages_dialogs = 0
@@ -97,10 +97,10 @@ class HTMLExporter {
             mustache = mf.compile("templates/html/chat.mustache")
 
             var i = 0
-            logger.debug("Generating {} dialog pages", dialogs.size())
+            logger.debug("Generating {} dialog pages", dialogs.size)
             for (d in dialogs) {
                 i++
-                logger.trace("Dialog {}/{}: {}", i, dialogs.size(), Utils.anonymize("" + d.id))
+                logger.trace("Dialog {}/{}: {}", i, dialogs.size, Utils.anonymize("" + d.id))
                 val messages = db.getMessagesForExport(d)
                 scope.clear()
                 scope.put("user", user)
@@ -118,10 +118,10 @@ class HTMLExporter {
             }
 
             i = 0
-            logger.debug("Generating {} chat pages", chats.size())
+            logger.debug("Generating {} chat pages", chats.size)
             for (c in chats) {
                 i++
-                logger.trace("Chat {}/{}: {}", i, chats.size(), Utils.anonymize("" + c.id))
+                logger.trace("Chat {}/{}: {}", i, chats.size, Utils.anonymize("" + c.id))
                 val messages = db.getMessagesForExport(c)
                 scope.clear()
                 scope.put("user", user)
@@ -140,7 +140,7 @@ class HTMLExporter {
 
             logger.debug("Generating additional files")
             // Copy CSS
-            val cssFile = getClass().getResource("/templates/html/style.css")
+            val cssFile = javaClass.getResource("/templates/html/style.css")
             val dest = File(base + "style.css")
             FileUtils.copyURLToFile(cssFile, dest)
             logger.debug("Done exporting.")
@@ -173,8 +173,8 @@ class HTMLExporter {
 
     private fun mapToString(map: Map<String, Integer>): String {
         val sb = StringBuilder("[")
-        for (entry in map.entrySet()) {
+        for ((key, value) in map) {
-            sb.append("['" + entry.getKey() + "', " + entry.getValue() + "],")
+            sb.append("['$key', $value],")
         }
         sb.append("]")
         return sb.toString()

src/main/kotlin/de/fabianonline/telegram_backup/mediafilemanager/AbstractMediaFileManager.kt

@@ -44,33 +44,34 @@ import java.util.concurrent.TimeoutException
 import org.apache.commons.io.FileUtils
 
 abstract class AbstractMediaFileManager(protected var message: TLMessage, protected var user: UserManager, protected var client: TelegramClient) {
-    var isEmpty = false
+    open var isEmpty = false
     abstract val size: Int
     abstract val extension: String
 
-    val downloaded: Boolean
+    open val downloaded: Boolean
     	get() = File(targetPathAndFilename).isFile()
     
     val downloading: Boolean
     	get() = File("${targetPathAndFilename}.downloading").isFile()
     
-	val targetPath: String
+	open val targetPath: String
 		get() {
-	        val path = user.getFileBase() + Config.FILE_FILES_BASE + File.separatorChar
+	        val path = user.fileBase + Config.FILE_FILES_BASE + File.separatorChar
     	    File(path).mkdirs()
     	    return path
 		}
     
-    val targetFilename: String
+    open val targetFilename: String
     	get() {
 			val message_id = message.getId()
-			if (message.getToId() is TLPeerChannel) {
+			var to = message.getToId()
-				val channel_id = message.getToId().getChannelId()
+			if (to is TLPeerChannel) {
+				val channel_id = to.getChannelId()
 				return "channel_${channel_id}_${message_id}.$extension"
 			} else return "${message_id}.$extension"
 		}
 
-    val targetPathAndFilenam: String
+    open val targetPathAndFilename: String
     	get() = targetPath + targetFilename
 
     abstract val letter: String
@@ -91,7 +92,9 @@ abstract class AbstractMediaFileManager(protected var message: TLMessage, protec
 
     }
 
-    fun throwUnexpectedObjectError(o: Object) {
+    companion object {
-        throw RuntimeException("Unexpected " + o.getClass().getName())
+    fun throwUnexpectedObjectError(o: Any) {
+        throw RuntimeException("Unexpected " + o.javaClass.getName())
+    }
     }
 }

src/main/kotlin/de/fabianonline/telegram_backup/mediafilemanager/DocumentFileManager.kt

@@ -42,26 +42,23 @@ import java.util.concurrent.TimeoutException
 
 import org.apache.commons.io.FileUtils
 
-class DocumentFileManager(msg: TLMessage, user: UserManager, client: TelegramClient) : AbstractMediaFileManager(msg, user, client) {
+open class DocumentFileManager(msg: TLMessage, user: UserManager, client: TelegramClient) : AbstractMediaFileManager(msg, user, client) {
     protected var doc: TLDocument? = null
-    private var extension: String? = null
+    override lateinit var extension: String
 
-    val isSticker: Boolean
+    open val isSticker: Boolean
         get() {
             var sticker: TLDocumentAttributeSticker? = null
             if (this.isEmpty || doc == null) return false
-            return doc!!.getAttributes()?.filter{it is TLDocumentAttributeSticker}.isNotEmpty()
+            return doc!!.getAttributes()?.filter{it is TLDocumentAttributeSticker}?.isNotEmpty() ?: false
         }
 
-    val size: Int
+    override val size: Int
         get() = if (doc != null) doc!!.getSize() else 0
 
-    val letter: String
+    open override val letter: String = "d"
-        get() = "d"
+    open override val name: String = "document"
-    val name: String
+    open override val description: String = "Document"
-        get() = "document"
-    val description: String
-        get() = "Document"
 
     init {
         val d = (msg.getMedia() as TLMessageMediaDocument).getDocument()
@@ -72,9 +69,10 @@ class DocumentFileManager(msg: TLMessage, user: UserManager, client: TelegramCli
         } else {
             throwUnexpectedObjectError(d)
         }
+        extension = processExtension()
     }
 
-    fun getExtension(): String? {
+    private fun processExtension(): String {
         if (extension != null) return extension
         if (doc == null) return "empty"
         var ext: String? = null
@@ -97,14 +95,13 @@ class DocumentFileManager(msg: TLMessage, user: UserManager, client: TelegramCli
         // Sometimes, extensions contain a trailing double quote. Remove this. Fixes #12.
         ext = ext!!.replace("\"", "")
 
-        this.extension = ext
         return ext
     }
 
     @Throws(RpcErrorException::class, IOException::class, TimeoutException::class)
-    fun download() {
+    override fun download() {
         if (doc != null) {
-            DownloadManager.downloadFile(client, getTargetPathAndFilename(), size, doc!!.getDcId(), doc!!.getId(), doc!!.getAccessHash())
+            DownloadManager.downloadFile(client, targetPathAndFilename, size, doc!!.getDcId(), doc!!.getId(), doc!!.getAccessHash())
         }
     }
 }

src/main/kotlin/de/fabianonline/telegram_backup/mediafilemanager/FileManagerFactory.kt

@@ -50,7 +50,7 @@ object FileManagerFactory {
             return PhotoFileManager(m, u, c)
         } else if (media is TLMessageMediaDocument) {
             val d = DocumentFileManager(m, u, c)
-            return if (d.isSticker()) {
+            return if (d.isSticker) {
                 StickerFileManager(m, u, c)
             } else d
         } else if (media is TLMessageMediaGeo) {

src/main/kotlin/de/fabianonline/telegram_backup/mediafilemanager/GeoFileManager.kt

@@ -44,24 +44,21 @@ import java.util.concurrent.TimeoutException
 import org.apache.commons.io.FileUtils
 
 class GeoFileManager(msg: TLMessage, user: UserManager, client: TelegramClient) : AbstractMediaFileManager(msg, user, client) {
-    protected var geo: TLGeoPoint
+    protected lateinit var geo: TLGeoPoint
 
     // We don't know the size, so we just guess.
-    val size: Int
+    override val size: Int
         get() {
-            val f = File(getTargetPathAndFilename())
+            val f = File(targetPathAndFilename)
-            return if (f.isFile()) f.length() else 100000
+            return if (f.isFile()) (f.length() as Int) else 100000
         }
 
-    val extension: String
+    override val extension: String
         get() = "png"
 
-    val letter: String
+    override val letter = "g"
-        get() = "g"
+    override val name = "geo"
-    val name: String
+    override val description = "Geolocation"
-        get() = "geo"
-    val description: String
-        get() = "Geolocation"
 
     init {
         val g = (msg.getMedia() as TLMessageMediaGeo).getGeo()
@@ -75,11 +72,11 @@ class GeoFileManager(msg: TLMessage, user: UserManager, client: TelegramClient)
     }
 
     @Throws(IOException::class)
-    fun download() {
+    override fun download() {
         val url = "https://maps.googleapis.com/maps/api/staticmap?" +
                 "center=" + geo.getLat() + "," + geo.getLong() + "&" +
                 "zoom=14&size=300x150&scale=2&format=png&" +
                 "key=" + Config.SECRET_GMAPS
-        DownloadManager.downloadExternalFile(getTargetPathAndFilename(), url)
+        DownloadManager.downloadExternalFile(targetPathAndFilename, url)
     }
 }

src/main/kotlin/de/fabianonline/telegram_backup/mediafilemanager/PhotoFileManager.kt

@@ -43,18 +43,14 @@ import java.util.concurrent.TimeoutException
 import org.apache.commons.io.FileUtils
 
 class PhotoFileManager(msg: TLMessage, user: UserManager, client: TelegramClient) : AbstractMediaFileManager(msg, user, client) {
-    private var photo: TLPhoto? = null
+    private lateinit var photo: TLPhoto
-    private var size: TLPhotoSize? = null
+    override var size = 0
+    private lateinit var photo_size: TLPhotoSize
 
-    val extension: String
+    override val extension = "jpg"
-        get() = "jpg"
+    override val letter = "p"
-
+    override val name = "photo"
-    val letter: String
+    override val description = "Photo"
-        get() = "p"
-    val name: String
-        get() = "photo"
-    val description: String
-        get() = "Photo"
 
     init {
         val p = (msg.getMedia() as TLMessageMediaPhoto).getPhoto()
@@ -72,7 +68,8 @@ class PhotoFileManager(msg: TLMessage, user: UserManager, client: TelegramClient
             if (biggest == null) {
                 throw RuntimeException("Could not find a size for a photo.")
             }
-            this.size = biggest
+            this.photo_size = biggest
+            this.size = biggest.getSize()
         } else if (p is TLPhotoEmpty) {
             this.isEmpty = true
         } else {
@@ -80,14 +77,10 @@ class PhotoFileManager(msg: TLMessage, user: UserManager, client: TelegramClient
         }
     }
 
-    fun getSize(): Int {
-        return if (size != null) size!!.getSize() else 0
-    }
-
     @Throws(RpcErrorException::class, IOException::class, TimeoutException::class)
-    fun download() {
+    override fun download() {
         if (isEmpty) return
-        val loc = size!!.getLocation() as TLFileLocation
+        val loc = photo_size.getLocation() as TLFileLocation
-        DownloadManager.downloadFile(client, getTargetPathAndFilename(), getSize(), loc.getDcId(), loc.getVolumeId(), loc.getLocalId(), loc.getSecret())
+        DownloadManager.downloadFile(client, targetPathAndFilename, size, loc.getDcId(), loc.getVolumeId(), loc.getLocalId(), loc.getSecret())
     }
 }

src/main/kotlin/de/fabianonline/telegram_backup/mediafilemanager/StickerFileManager.kt

@@ -52,13 +52,12 @@ import org.apache.commons.io.FileUtils
 
 class StickerFileManager(msg: TLMessage, user: UserManager, client: TelegramClient) : DocumentFileManager(msg, user, client) {
 
-    val isSticker: Boolean
+    override val isSticker = true
-        get() = true
 
     private val filenameBase: String
         get() {
             var sticker: TLDocumentAttributeSticker? = null
-            for (attr in doc.getAttributes()) {
+            for (attr in doc!!.getAttributes()) {
                 if (attr is TLDocumentAttributeSticker) {
                     sticker = attr as TLDocumentAttributeSticker
                 }
@@ -75,34 +74,33 @@ class StickerFileManager(msg: TLMessage, user: UserManager, client: TelegramClie
             return file.toString()
         }
 
-    val targetFilename: String
+    override val targetFilename: String
         get() = filenameBase + "." + extension
 
-    val targetPath: String
+    override val targetPath: String
         get() {
-            val path = user.getFileBase() + Config.FILE_FILES_BASE + File.separatorChar + Config.FILE_STICKER_BASE + File.separatorChar
+            val path = user.fileBase + Config.FILE_FILES_BASE + File.separatorChar + Config.FILE_STICKER_BASE + File.separatorChar
             File(path).mkdirs()
             return path
         }
 
-    val extension: String
+    override var extension = "webp"
-        get() = "webp"
 
-    val letter: String
+    override val letter: String
         get() = "s"
-    val name: String
+    override val name: String
         get() = "sticker"
-    val description: String
+    override val description: String
         get() = "Sticker"
 
     @Throws(RpcErrorException::class, IOException::class, TimeoutException::class)
-    fun download() {
+    override fun download() {
         val old_file = Config.FILE_BASE + File.separatorChar + Config.FILE_STICKER_BASE + File.separatorChar + targetFilename
 
         logger.trace("Old filename exists: {}", File(old_file).exists())
 
         if (File(old_file).exists()) {
-            Files.copy(Paths.get(old_file), Paths.get(getTargetPathAndFilename()), StandardCopyOption.REPLACE_EXISTING)
+            Files.copy(Paths.get(old_file), Paths.get(targetPathAndFilename), StandardCopyOption.REPLACE_EXISTING)
             return
         }
         super.download()

src/main/kotlin/de/fabianonline/telegram_backup/mediafilemanager/UnsupportedFileManager.kt

@@ -44,34 +44,15 @@ import java.util.concurrent.TimeoutException
 import org.apache.commons.io.FileUtils
 
 class UnsupportedFileManager(msg: TLMessage, user: UserManager, client: TelegramClient, type: String) : AbstractMediaFileManager(msg, user, client) {
-    var name: String? = null
+    override var name = type
-        internal set
+    override val targetFilename = ""
+    override val targetPath = ""
+    override val extension = ""
+    override val size = 0
+    override var isEmpty = false
+    override val downloaded = false
+    override val letter = " "
+    override val description = "Unsupported / non-downloadable Media"
     
-    val targetFilename: String
+    override fun download() {}
-        get() = ""
-
-    val targetPath: String
-        get() = ""
-
-    val extension: String
-        get() = ""
-
-    val size: Int
-        get() = 0
-
-    val isEmpty: Boolean
-        get() = false
-    val isDownloaded: Boolean
-        get() = false
-
-    val letter: String
-        get() = " "
-    val description: String
-        get() = "Unsupported / non-downloadable Media"
-
-    init {
-        this.name = type
-    }
-
-    fun download() {}
 }