Kotlin: It now compiles without any errors and / or warnings. But running it fails because raw JDBC isn't very Kotlin compatible, it seems.

build.gradle

@@ -1,7 +1,7 @@
 apply plugin: 'java'
 apply plugin: 'application'
 
-mainClassName= 'de.fabianonline.telegram_backup.CommandLineRunner'
+mainClassName= 'de.fabianonline.telegram_backup.CommandLineRunnerKt'
 
 repositories {
 	mavenCentral()

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

@@ -87,8 +87,8 @@ internal class ApiStorage(prefix: String?) : TelegramApiStorage {
         return null
     }
 
-    override fun saveDc(dc: DataCenter) {
+    override fun saveDc(dataCenter: DataCenter) {
-        this.dc = dc
+        this.dc = dataCenter
         this._saveDc()
     }
 

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

@@ -115,13 +115,13 @@ class CommandLineController {
       }
       if (CommandLineOptions.val_test != null)
       {
-        if (CommandLineOptions.val_test === 1)
+        if (CommandLineOptions.val_test == 1)
         {
           TestFeatures.test1()
         }
-        else if (CommandLineOptions.val_test === 2)
+        else if (CommandLineOptions.val_test == 2)
         {
-          TestFeatures.test2(user, client)
+          TestFeatures.test2()
         }
         else
         {

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

@@ -54,15 +54,15 @@ internal class CommandLineDownloadProgress : DownloadProgressInterface {
         println("" + count + " Files to check / download")
     }
 
-    override fun onMediaDownloaded(fm: AbstractMediaFileManager) {
+    override fun onMediaDownloaded(file_manager: AbstractMediaFileManager) {
-        show(fm.letter.toUpperCase())
+        show(file_manager.letter.toUpperCase())
     }
 
     override fun onMediaDownloadedEmpty() {
         show("e")
     }
 
-    override fun onMediaAlreadyPresent(fm: AbstractMediaFileManager) {
+    override fun onMediaAlreadyPresent(file_manager: AbstractMediaFileManager) {
         show(".")
     }
 

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

@@ -27,12 +27,11 @@ import ch.qos.logback.classic.spi.ILoggingEvent
 import ch.qos.logback.core.ConsoleAppender
 import ch.qos.logback.classic.Level
 
-object CommandLineRunner {
     fun main(args: Array<String>) {
         CommandLineOptions.parseOptions(args)
 
-        setupLogging()
+        CommandLineRunner.setupLogging()
-        checkVersion()
+        CommandLineRunner.checkVersion()
 
 
 
@@ -44,8 +43,10 @@ object CommandLineRunner {
         }
     }
 
+object CommandLineRunner {
     fun setupLogging() {
         val logger = LoggerFactory.getLogger(CommandLineRunner::class.java) as Logger
+        logger.trace("Setting up Loggers...")
         val rootLogger = LoggerFactory.getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME) as Logger
         val rootContext = rootLogger.getLoggerContext()
         rootContext.reset()
@@ -76,14 +77,14 @@ object CommandLineRunner {
 
     fun checkVersion(): Boolean {
         val v = Utils.getNewestVersion()
-        if (v != null && v!!.isNewer) {
+        if (v != null && v.isNewer) {
             System.out.println("A newer version is vailable!")
             System.out.println("You are using: " + Config.APP_APPVER)
-            System.out.println("Available:     " + v!!.version)
+            System.out.println("Available:     " + v.version)
-            System.out.println("Get it here:   " + v!!.url)
+            System.out.println("Get it here:   " + v.url)
             System.out.println()
             System.out.println("Changes in this version:")
-            System.out.println(v!!.body)
+            System.out.println(v.body)
             System.out.println()
             return false
         }

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

@@ -49,7 +49,7 @@ object Config {
     init {
         val p = Properties()
         try {
-            p.load(Config::class.java!!.getResourceAsStream("/build.properties"))
+            p.load(Config::class.java.getResourceAsStream("/build.properties"))
             APP_APPVER = p.getProperty("version")
         } catch (e: IOException) {
             throw RuntimeException(e)

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

@@ -132,8 +132,7 @@ class Database private constructor(var client: TelegramClient) {
                 val rs = stmt!!.executeQuery("SELECT COUNT(id), api_layer FROM messages GROUP BY api_layer ORDER BY api_layer")
                 while (rs.next()) {
                     var layer = rs.getInt(2)
-                    if (layer == null) layer = 0
+                    map.put("count.messages.api_layer.$layer", rs.getInt(1))
-                    map.put("count.messages.api_layer." + layer!!, rs.getInt(1))
                 }
                 rs.close()
                 return map
@@ -286,15 +285,15 @@ class Database private constructor(var client: TelegramClient) {
 
             for (abs in all) {
                 if (abs is TLMessage) {
-                    val msg = abs as TLMessage
+                    val msg = abs
                     ps.setInt(1, msg.getId())
                     ps.setString(2, "message")
                     val peer = msg.getToId()
                     if (peer is TLPeerChat) {
                         ps.setString(3, "group")
-                        ps.setInt(4, (peer as TLPeerChat).getChatId())
+                        ps.setInt(4, peer.getChatId())
                     } else if (peer is TLPeerUser) {
-                        var id = (peer as TLPeerUser).getUserId()
+                        var id = peer.getUserId()
                         if (id == this.user_manager.user!!.getId()) {
                             id = msg.getFromId()
                         }
@@ -321,11 +320,12 @@ class Database private constructor(var client: TelegramClient) {
                     }
 
                     var text = msg.getMessage()
-                    if ((text == null || text!!.equals("")) && msg.getMedia() != null) {
+                    if ((text == null || text.equals("")) && msg.getMedia() != null) {
-                        if (msg.getMedia() is TLMessageMediaDocument) {
+                    	val media = msg.getMedia()
-                            text = (msg.getMedia() as TLMessageMediaDocument).getCaption()
+                        if (media is TLMessageMediaDocument) {
-                        } else if (msg.getMedia() is TLMessageMediaPhoto) {
+                        	text = media.getCaption()
-                            text = (msg.getMedia() as TLMessageMediaPhoto).getCaption()
+                        } else if (media is TLMessageMediaPhoto) {
+                            text = media.getCaption()
                         }
                     }
                     ps.setString(7, text)
@@ -419,19 +419,19 @@ class Database private constructor(var client: TelegramClient) {
                     ps_insert_or_ignore.setString(3, "empty_chat")
                     ps_insert_or_ignore.addBatch()
                 } else if (abs is TLChatForbidden) {
-                    ps_insert_or_replace.setString(2, (abs as TLChatForbidden).getTitle())
+                    ps_insert_or_replace.setString(2, abs.getTitle())
                     ps_insert_or_replace.setString(3, "chat")
                     ps_insert_or_replace.addBatch()
                 } else if (abs is TLChannelForbidden) {
-                    ps_insert_or_replace.setString(2, (abs as TLChannelForbidden).getTitle())
+                    ps_insert_or_replace.setString(2, abs.getTitle())
                     ps_insert_or_replace.setString(3, "channel")
                     ps_insert_or_replace.addBatch()
                 } else if (abs is TLChat) {
-                    ps_insert_or_replace.setString(2, (abs as TLChat).getTitle())
+                    ps_insert_or_replace.setString(2, abs.getTitle())
                     ps_insert_or_replace.setString(3, "chat")
                     ps_insert_or_replace.addBatch()
                 } else if (abs is TLChannel) {
-                    ps_insert_or_replace.setString(2, (abs as TLChannel).getTitle())
+                    ps_insert_or_replace.setString(2, abs.getTitle())
                     ps_insert_or_replace.setString(3, "channel")
                     ps_insert_or_replace.addBatch()
                 } else {
@@ -467,7 +467,7 @@ class Database private constructor(var client: TelegramClient) {
                             "(?,  ?,          ?,         ?,        ?,    ?)")
             for (abs in all) {
                 if (abs is TLUser) {
-                    val user = abs as TLUser
+                    val user = abs
                     ps_insert_or_replace.setInt(1, user.getId())
                     ps_insert_or_replace.setString(2, user.getFirstName())
                     ps_insert_or_replace.setString(3, user.getLastName())
@@ -542,7 +542,7 @@ class Database private constructor(var client: TelegramClient) {
                 } else {
                     count += rs.getInt(2)
                 }
-                map.put("count.messages.media_type." + s!!, rs.getInt(2))
+                map.put("count.messages.media_type.$s", rs.getInt(2))
             }
             map.put("count.messages.media_type.any", count)
             return map
@@ -567,9 +567,9 @@ class Database private constructor(var client: TelegramClient) {
             while (rs.next()) {
                 val u: User
                 if (rs.getString(2) != null || rs.getString(3) != null || rs.getString(4) != null) {
-                    u = User(rs.getInt(1), rs.getString(2), rs.getString(3), rs.getString(4))
+                    u = User(rs.getInt(1), rs.getString(2), rs.getString(3))
                 } else {
-                    u = User(rs.getInt(1), "Unknown", "", "")
+                    u = User(rs.getInt(1), "Unknown", "")
                 }
                 if (u.isMe) {
                     map.put("authors.count.me", rs.getInt(5))
@@ -595,7 +595,7 @@ class Database private constructor(var client: TelegramClient) {
                     "COUNT(id) FROM messages WHERE " + c.query + " GROUP BY hour, day " +
                     "ORDER BY hour, day")
             while (rs.next()) {
-                result[if (rs.getInt(1) === 0) 6 else rs.getInt(1) - 1][rs.getInt(2)] = rs.getInt(3)
+                result[if (rs.getInt(1) == 0) 6 else rs.getInt(1) - 1][rs.getInt(2)] = rs.getInt(3)
             }
             return result
         } catch (e: Exception) {
@@ -638,10 +638,10 @@ 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.user!!.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)
+                h.put("same_user", old_user != 0 && rs.getInt("user_id") == old_user)
                 old_user = rs.getInt("user_id")
                 old_date = date
 
@@ -674,7 +674,7 @@ class Database private constructor(var client: TelegramClient) {
             get() = "source_type IN('group', 'supergroup', 'channel') AND source_id=" + id
     }
 
-    inner class User(id: Int, first_name: String?, last_name: String?, username: String) {
+    inner class User(id: Int, first_name: String?, last_name: String?) {
         var name: String
         var isMe: Boolean = false
 

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

@@ -43,7 +43,7 @@ class DatabaseUpdates(protected var conn: Connection, protected var db: Database
             logger.debug("Checking if table database_versions exists")
             rs = stmt.executeQuery("SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='database_versions'")
             rs.next()
-            if (rs.getInt(1) === 0) {
+            if (rs.getInt(1) == 0) {
                 logger.debug("Table does not exist")
                 version = 0
             } else {
@@ -286,10 +286,10 @@ internal class DB_Update_6(conn: Connection, db: Database) : DatabaseUpdate(conn
         while (rs.next()) {
             ps.setInt(5, rs.getInt(1))
             val msg = Database.bytesToTLMessage(rs.getBytes(2))
-            if (msg == null || msg!!.getFwdFrom() == null) {
+            if (msg == null || msg.getFwdFrom() == null) {
                 ps.setNull(1, Types.INTEGER)
             } else {
-                ps.setInt(1, msg!!.getFwdFrom().getFromId())
+                ps.setInt(1, msg.getFwdFrom().getFromId())
             }
             val f = FileManagerFactory.getFileManager(msg, db.user_manager, db.client)
             if (f == null) {

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

@@ -66,13 +66,13 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
 
     @Throws(RpcErrorException::class, IOException::class)
     fun downloadMessages(limit: Int?) {
-        var completed = true
+        var completed: Boolean
         do {
             completed = true
             try {
                 _downloadMessages(limit)
             } catch (e: RpcErrorException) {
-                if (e.getCode() === 420) { // FLOOD_WAIT
+                if (e.getCode() == 420) { // FLOOD_WAIT
                     completed = false
                     Utils.obeyFloodWaitException(e)
                 } else {
@@ -118,8 +118,8 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
         var max_database_id = db!!.getTopMessageID()
         System.out.println("Top message ID in database is " + max_database_id)
         if (limit != null) {
-            System.out.println("Limit is set to " + limit!!)
+            System.out.println("Limit is set to " + limit)
-            max_database_id = Math.max(max_database_id, max_message_id - limit!!)
+            max_database_id = Math.max(max_database_id, max_message_id - limit)
             System.out.println("New top message id 'in database' is " + max_database_id)
         }
         if (max_message_id - max_database_id > 1000000) {
@@ -142,7 +142,6 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
         }
 
         logger.info("Searching for missing messages in the db")
-        val count_missing = 0
         System.out.println("Checking message database for completeness...")
         val db_count = db!!.getMessageCount()
         val db_max = db!!.getTopMessageID()
@@ -182,10 +181,9 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
             // TODO Add chat title (and other stuff?) to the database
             for (c in dialogs.getChats()) {
                 if (c is TLChannel) {
-                    val ch = c as TLChannel
+                    channel_access_hashes.put(c.getId(), c.getAccessHash())
-                    channel_access_hashes.put(c.getId(), ch.getAccessHash())
+                    channel_names.put(c.getId(), c.getTitle())
-                    channel_names.put(c.getId(), ch.getTitle())
+                    if (c.getMegagroup()) {
-                    if (ch.getMegagroup()) {
                         supergroups.add(c.getId())
                     } else {
                         channels.add(c.getId())
@@ -216,7 +214,7 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
                             channel_name = "?"
                         }
                         val channel = TLInputChannel(channel_id, access_hash)
-                        downloadMessages(ids, channel, "channel " + channel_name!!)
+                        downloadMessages(ids, channel, "channel $channel_name")
                     }
                 }
             }
@@ -234,7 +232,7 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
             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.removeAt(0))
             }
             logger.trace("vector.size(): {}", vector.size)
@@ -256,7 +254,7 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
                     }
                     break
                 } catch (e: RpcErrorException) {
-                    if (e.getCode() === 420) { // FLOOD_WAIT
+                    if (e.getCode() == 420) { // FLOOD_WAIT
                         Utils.obeyFloodWaitException(e, has_seen_flood_wait_message)
                         has_seen_flood_wait_message = true
                     } else {
@@ -266,7 +264,7 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
 
             }
             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.")
             }
 
@@ -289,7 +287,7 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
     @Throws(RpcErrorException::class, IOException::class)
     fun downloadMedia() {
         download_client = client!!.getDownloaderClient()
-        var completed = true
+        var completed: Boolean
         do {
             completed = true
             try {
@@ -367,19 +365,19 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
         internal val logger = LoggerFactory.getLogger(DownloadManager::class.java)
 
         @Throws(RpcErrorException::class, IOException::class, TimeoutException::class)
-        fun downloadFile(client: TelegramClient, targetFilename: String, size: Int, dcId: Int, volumeId: Long, localId: Int, secret: Long) {
+        fun downloadFile(targetFilename: String, size: Int, dcId: Int, volumeId: Long, localId: Int, secret: Long) {
             val loc = TLInputFileLocation(volumeId, localId, secret)
-            downloadFileFromDc(client, targetFilename, loc, dcId, size)
+            downloadFileFromDc(targetFilename, loc, dcId, size)
         }
 
         @Throws(RpcErrorException::class, IOException::class, TimeoutException::class)
-        fun downloadFile(client: TelegramClient, targetFilename: String, size: Int, dcId: Int, id: Long, accessHash: Long) {
+        fun downloadFile(targetFilename: String, size: Int, dcId: Int, id: Long, accessHash: Long) {
             val loc = TLInputDocumentFileLocation(id, accessHash)
-            downloadFileFromDc(client, targetFilename, loc, dcId, size)
+            downloadFileFromDc(targetFilename, loc, dcId, size)
         }
 
         @Throws(RpcErrorException::class, IOException::class, TimeoutException::class)
-        private fun downloadFileFromDc(client: TelegramClient, target: String, loc: TLAbsInputFileLocation, dcID: Int, size: Int): Boolean {
+        private fun downloadFileFromDc(target: String, loc: TLAbsInputFileLocation, dcID: Int, size: Int): Boolean {
             var fos: FileOutputStream? = null
             try {
                 val temp_filename = target + ".downloading"
@@ -389,7 +387,7 @@ 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() as Int
+                    offset = File(temp_filename).length().toInt()
                     if (offset >= size) {
                         logger.warn("Temporary file size is >= the target size. Assuming corrupt file & deleting it")
                         File(temp_filename).delete()
@@ -405,18 +403,13 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
                     logger.trace("offset: {} block_size: {} size: {}", offset, size, size)
                     val req = TLRequestUploadGetFile(loc, offset, size)
                     try {
-                        if (dcID == null) {
-                            response = download_client!!.executeRpcQuery(req) as TLFile
-                        } else {
                         response = download_client!!.executeRpcQuery(req, dcID) as TLFile
-                        }
                     } catch (e: RpcErrorException) {
                         if (e.getTag().startsWith("420: FLOOD_WAIT_")) {
                             try_again = true
                             Utils.obeyFloodWaitException(e)
-                        } else if (e.getCode() === 400) {
+                        } else if (e.getCode() == 400) {
                             //Somehow this file is broken. No idea why. Let's skip it for now
-                            try_again = true
                             return false
                         } else {
                             throw e
@@ -424,17 +417,17 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
                     }
 
                     offset += response!!.getBytes().getData().size
-                    logger.trace("response: {} total size: {}", response!!.getBytes().getData().size, offset)
+                    logger.trace("response: {} total size: {}", response.getBytes().getData().size, offset)
 
-                    fos!!.write(response!!.getBytes().getData())
+                    fos.write(response.getBytes().getData())
-                    fos!!.flush()
+                    fos.flush()
                     try {
                         TimeUnit.MILLISECONDS.sleep(Config.DELAY_AFTER_GET_FILE)
                     } catch (e: InterruptedException) {
                     }
 
                 } while (offset < size && (response!!.getBytes().getData().size > 0 || try_again))
-                fos!!.close()
+                fos.close()
                 if (offset < size) {
                     System.out.println("Requested file $target with $size bytes, but got only $offset bytes.")
                     File(temp_filename).delete()
@@ -466,12 +459,12 @@ class DownloadManager(internal var client: TelegramClient?, p: DownloadProgressI
                 last_download_succeeded = true
                 return true
             } catch (ex: java.io.IOException) {
-                if (fos != null) fos!!.close()
+                if (fos != null) fos.close()
                 System.out.println("IOException happened while downloading " + target)
                 throw ex
             } catch (ex: RpcErrorException) {
-                if (fos != null) fos!!.close()
+                if (fos != null) fos.close()
-                if (ex.getCode() === 500) {
+                if (ex.getCode() == 500) {
                     if (!last_download_succeeded) {
                         System.out.println("Got an Internal Server Error from Telegram. Since the file downloaded before also happened to get this error, we will stop downloading now. Please try again later.")
                         throw ex

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

@@ -24,9 +24,9 @@ interface DownloadProgressInterface {
     fun onMessageDownloadFinished()
 
     fun onMediaDownloadStart(count: Int)
-    fun onMediaDownloaded(a: AbstractMediaFileManager)
+    fun onMediaDownloaded(file_manager: AbstractMediaFileManager)
     fun onMediaDownloadedEmpty()
     fun onMediaSkipped()
-    fun onMediaAlreadyPresent(a: AbstractMediaFileManager)
+    fun onMediaAlreadyPresent(file_manager: AbstractMediaFileManager)
     fun onMediaDownloadFinished()
 }

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

@@ -33,7 +33,7 @@ class TLRequestAccountGetPasswordWithCurrentSalt : TLMethod<TLPassword>() {
     @Throws(IOException::class)
     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
+        return response
     }
 
     override fun toString(): String {

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

@@ -37,64 +37,65 @@ internal class TelegramUpdateHandler : UpdateCallback {
         this.db = Database.getInstance()
     }
 
-    override fun onUpdates(c: TelegramClient, u: TLUpdates) {
+    override fun onUpdates(client: TelegramClient, updates: 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 - " + updates.getUpdates().size + " Updates, " + updates.getUsers().size + " Users, " + updates.getChats().size + " Chats")
-        for (update in u.getUpdates()) {
+        for (update in updates.getUpdates()) {
-            processUpdate(update, c)
+            processUpdate(update, client)
             if (debug) System.out.println("  " + update.javaClass.getName())
         }
-        db!!.saveUsers(u.getUsers())
+        db!!.saveUsers(updates.getUsers())
-        db!!.saveChats(u.getChats())
+        db!!.saveChats(updates.getChats())
     }
 
-    override fun onUpdatesCombined(c: TelegramClient, u: TLUpdatesCombined) {
+    override fun onUpdatesCombined(client: TelegramClient, updates: TLUpdatesCombined) {
         if (db == null) return
         if (debug) System.out.println("onUpdatesCombined")
-        for (update in u.getUpdates()) {
+        for (update in updates.getUpdates()) {
-            processUpdate(update, c)
+            processUpdate(update, client)
         }
-        db!!.saveUsers(u.getUsers())
+        db!!.saveUsers(updates.getUsers())
-        db!!.saveChats(u.getChats())
+        db!!.saveChats(updates.getChats())
     }
 
-    override fun onUpdateShort(c: TelegramClient, u: TLUpdateShort) {
+    override fun onUpdateShort(client: TelegramClient, update: TLUpdateShort) {
         if (db == null) return
         if (debug) System.out.println("onUpdateShort")
-        processUpdate(u.getUpdate(), c)
+        processUpdate(update.getUpdate(), client)
-        if (debug) System.out.println("  " + u.getUpdate().javaClass.getName())
+        if (debug) System.out.println("  " + update.getUpdate().javaClass.getName())
     }
 
-    override fun onShortChatMessage(c: TelegramClient, m: TLUpdateShortChatMessage) {
+    override fun onShortChatMessage(client: TelegramClient, message: TLUpdateShortChatMessage) {
         if (db == null) return
-        if (debug) System.out.println("onShortChatMessage - " + m.getMessage())
+        if (debug) System.out.println("onShortChatMessage - " + message.getMessage())
         val msg = TLMessage(
-                m.getOut(),
+                message.getOut(),
-                m.getMentioned(),
+                message.getMentioned(),
-                m.getMediaUnread(),
+                message.getMediaUnread(),
-                m.getSilent(),
+                message.getSilent(),
                 false,
-                m.getId(),
+                message.getId(),
-                m.getFromId(),
+                message.getFromId(),
-                TLPeerChat(m.getChatId()),
+                TLPeerChat(message.getChatId()),
-                m.getFwdFrom(),
+                message.getFwdFrom(),
-                m.getViaBotId(),
+                message.getViaBotId(),
-                m.getReplyToMsgId(),
+                message.getReplyToMsgId(),
-                m.getDate(),
+                message.getDate(),
-                m.getMessage(), null, null,
+                message.getMessage(), null, null,
-                m.getEntities(), null, null)
+                message.getEntities(), null, null)
         val vector = TLVector<TLAbsMessage>(TLAbsMessage::class.java)
         vector.add(msg)
         db!!.saveMessages(vector, Kotlogram.API_LAYER)
         System.out.print('.')
     }
 
-    override fun onShortMessage(c: TelegramClient, m: TLUpdateShortMessage) {
+    override fun onShortMessage(client: TelegramClient, message: TLUpdateShortMessage) {
+    	val m = message
         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) {
+        if (m.getOut() == true) {
             from_id = user!!.user!!.getId()
             to_id = m.getUserId()
         } else {
@@ -122,28 +123,28 @@ internal class TelegramUpdateHandler : UpdateCallback {
         System.out.print('.')
     }
 
-    override fun onShortSentMessage(c: TelegramClient, m: TLUpdateShortSentMessage) {
+    override fun onShortSentMessage(client: TelegramClient, message: TLUpdateShortSentMessage) {
         if (db == null) return
         System.out.println("onShortSentMessage")
     }
 
-    override fun onUpdateTooLong(c: TelegramClient) {
+    override fun onUpdateTooLong(client: TelegramClient) {
         if (db == null) return
         System.out.println("onUpdateTooLong")
     }
 
     private fun processUpdate(update: TLAbsUpdate, client: TelegramClient) {
         if (update is TLUpdateNewMessage) {
-            val abs_msg = (update as TLUpdateNewMessage).getMessage()
+            val abs_msg = update.getMessage()
             val vector = TLVector<TLAbsMessage>(TLAbsMessage::class.java)
             vector.add(abs_msg)
             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, user!!, client)
-                if (fm != null && !fm!!.isEmpty && !fm!!.downloaded) {
+                if (fm != null && !fm.isEmpty && !fm.downloaded) {
                     try {
-                        fm!!.download()
+                        fm.download()
                     } catch (e: Exception) {
                         System.out.println("We got an exception while downloading media, but we're going to ignore it.")
                         System.out.println("Here it is anyway:")

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

@@ -21,12 +21,12 @@ internal object TestFeatures {
 
         val path = "jdbc:sqlite:cache4.db"
 
-        var conn: Connection? = null
+        var conn: Connection
         var stmt: Statement? = null
 
         try {
             conn = DriverManager.getConnection(path)
-            stmt = conn!!.createStatement()
+            stmt = conn.createStatement()
         } catch (e: SQLException) {
             CommandLineController.show_error("Could not connect to SQLITE database.")
         }
@@ -55,7 +55,7 @@ internal object TestFeatures {
         System.out.println("Unsupported constructor: " + unsupported_constructor)
     }
 
-    fun test2(user: UserManager, client: TelegramClient) {
+    fun test2() {
         // Prints system.encoding and default charset
         System.out.println("Default Charset:   " + Charset.defaultCharset())
         System.out.println("file.encoding:     " + System.getProperty("file.encoding"))

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

@@ -74,7 +74,7 @@ private constructor(c: TelegramClient) {
         this.client = c
         logger.debug("Calling getFullUser")
         try {
-            val full_user = this.client!!.usersGetFullUser(TLInputUserSelf())
+            val full_user = this.client.usersGetFullUser(TLInputUserSelf())
             this.user = full_user.getUser().getAsUser()
         } catch (e: RpcErrorException) {
             // This may happen. Ignoring it.
@@ -86,17 +86,17 @@ private constructor(c: TelegramClient) {
     @Throws(RpcErrorException::class, IOException::class)
     fun sendCodeToPhoneNumber(number: String) {
         this.phone = number
-        this.sent_code = this.client!!.authSendCode(false, number, true)
+        this.sent_code = this.client.authSendCode(false, number, true)
     }
 
     @Throws(RpcErrorException::class, IOException::class)
     fun verifyCode(code: String) {
         this.code = code
         try {
-            this.auth = client!!.authSignIn(phone, this.sent_code!!.getPhoneCodeHash(), this.code)
+            this.auth = client.authSignIn(phone, this.sent_code!!.getPhoneCodeHash(), this.code)
             this.user = auth!!.getUser().getAsUser()
         } catch (e: RpcErrorException) {
-            if (e.getCode() !== 401 || !e.getTag().equals("SESSION_PASSWORD_NEEDED")) throw e
+            if (e.getCode() != 401 || !e.getTag().equals("SESSION_PASSWORD_NEEDED")) throw e
             this.isPasswordNeeded = true
         }
 
@@ -105,8 +105,8 @@ private constructor(c: TelegramClient) {
     @Throws(RpcErrorException::class, IOException::class)
     fun verifyPassword(pw: String) {
         val password = pw.toByteArray(charset=Charsets.UTF_8)
-        val salt = (client!!.accountGetPassword() as TLPassword).getCurrentSalt().getData()
+        val salt = (client.accountGetPassword() as TLPassword).getCurrentSalt().getData()
-        var md: MessageDigest? = null
+        var md: MessageDigest
         try {
             md = MessageDigest.getInstance("SHA-256")
         } catch (e: NoSuchAlgorithmException) {
@@ -118,8 +118,8 @@ private constructor(c: TelegramClient) {
         System.arraycopy(salt, 0, salted, 0, salt.size)
         System.arraycopy(password, 0, salted, salt.size, password.size)
         System.arraycopy(salt, 0, salted, salt.size + password.size, salt.size)
-        val hash = md!!.digest(salted)
+        val hash = md.digest(salted)
-        auth = client!!.authCheckPassword(TLBytes(hash))
+        auth = client.authCheckPassword(TLBytes(hash))
         this.user = auth!!.getUser().getAsUser()
     }
 

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

@@ -28,9 +28,9 @@ import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 
 object Utils {
-    val VERSIONS_EQUAL = 0
+    @JvmField public val VERSIONS_EQUAL = 0
-    val VERSION_1_NEWER = 1
+    @JvmField public val VERSION_1_NEWER = 1
-    val VERSION_2_NEWER = 2
+    @JvmField public val VERSION_2_NEWER = 2
 
     private val logger = LoggerFactory.getLogger(Utils::class.java) as Logger
 
@@ -39,7 +39,7 @@ object Utils {
             val folder = File(Config.FILE_BASE)
             val files = folder.listFiles()
             if (files != null)
-                for (f in files!!) {
+                for (f in files) {
                     if (f.isDirectory() && f.getName().startsWith("+")) {
                         accounts.add(f.getName())
                     }
@@ -60,19 +60,19 @@ object Utils {
                     for (e in root)
                         if (e.isJsonObject()) {
                             val version = e.getAsJsonObject()
-                            if (version.getAsJsonPrimitive("prerelease").getAsBoolean() === false) {
+                            if (version.getAsJsonPrimitive("prerelease").getAsBoolean() == false) {
                                 newest_version = version
                                 break
                             }
                         }
                     if (newest_version == null) return null
-                    val new_v = newest_version!!.getAsJsonPrimitive("tag_name").getAsString()
+                    val new_v = newest_version.getAsJsonPrimitive("tag_name").getAsString()
                     logger.debug("Found current release version {}", new_v)
                     val cur_v = Config.APP_APPVER
 
                     val result = compareVersions(cur_v, new_v)
 
-                    return Version(new_v, newest_version!!.getAsJsonPrimitive("html_url").getAsString(), newest_version!!.getAsJsonPrimitive("body").getAsString(), result == VERSION_2_NEWER)
+                    return Version(new_v, newest_version.getAsJsonPrimitive("html_url").getAsString(), newest_version.getAsJsonPrimitive("body").getAsString(), result == VERSION_2_NEWER)
                 }
                 return null
             } catch (e: Exception) {
@@ -83,14 +83,14 @@ object Utils {
 
     @Throws(RpcErrorException::class)
     @JvmOverloads internal fun obeyFloodWaitException(e: RpcErrorException?, silent: Boolean = false) {
-        if (e == null || e!!.getCode() !== 420) return
+        if (e == null || e.getCode() != 420) return
 
-        val delay: Long = e!!.getTagInteger()!! as Long
+        val delay: Long = e.getTagInteger()!!.toLong()
         if (!silent) {
             System.out.println("")
             System.out.println(
                     "Telegram complained about us (okay, me) making too many requests in too short time by\n" +
-                            "sending us \"" + e!!.getTag() + "\" as an error. So we now have to wait a bit. Telegram\n" +
+                            "sending us \"" + e.getTag() + "\" as an error. So we now have to wait a bit. Telegram\n" +
                             "asked us to wait for " + delay + " seconds.\n" +
                             "\n" +
                             "So I'm going to do just that for now. If you don't want to wait, you can quit by pressing\n" +
@@ -106,6 +106,7 @@ object Utils {
 
     }
 
+    @JvmStatic
     fun compareVersions(v1: String, v2: String): Int {
         logger.debug("Comparing versions {} and {}.", v1, v2)
         if (v1.equals(v2)) return VERSIONS_EQUAL

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

@@ -171,7 +171,7 @@ class HTMLExporter {
         return sb.toString()
     }
 
-    private fun mapToString(map: Map<String, Integer>): String {
+    private fun mapToString(map: Map<String, Int>): String {
         val sb = StringBuilder("[")
         for ((key, value) in map) {
             sb.append("['$key', $value],")

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

@@ -48,7 +48,6 @@ open class DocumentFileManager(msg: TLMessage, user: UserManager, client: Telegr
 
     open val isSticker: Boolean
         get() {
-            var sticker: TLDocumentAttributeSticker? = null
             if (this.isEmpty || doc == null) return false
             return doc!!.getAttributes()?.filter{it is TLDocumentAttributeSticker}?.isNotEmpty() ?: false
         }
@@ -63,7 +62,7 @@ open class DocumentFileManager(msg: TLMessage, user: UserManager, client: Telegr
     init {
         val d = (msg.getMedia() as TLMessageMediaDocument).getDocument()
         if (d is TLDocument) {
-            this.doc = d as TLDocument
+            this.doc = d
         } else if (d is TLDocumentEmpty) {
             this.isEmpty = true
         } else {
@@ -73,14 +72,13 @@ open class DocumentFileManager(msg: TLMessage, user: UserManager, client: Telegr
     }
 
     private fun processExtension(): String {
-        if (extension != null) return extension
         if (doc == null) return "empty"
         var ext: String? = null
         var original_filename: String? = null
         if (doc!!.getAttributes() != null)
             for (attr in doc!!.getAttributes()) {
                 if (attr is TLDocumentAttributeFilename) {
-                    original_filename = (attr as TLDocumentAttributeFilename).getFileName()
+                    original_filename = attr.getFileName()
                 }
             }
         if (original_filename != null) {
@@ -93,7 +91,7 @@ open class DocumentFileManager(msg: TLMessage, user: UserManager, client: Telegr
         }
 
         // Sometimes, extensions contain a trailing double quote. Remove this. Fixes #12.
-        ext = ext!!.replace("\"", "")
+        ext = ext.replace("\"", "")
 
         return ext
     }
@@ -101,7 +99,7 @@ open class DocumentFileManager(msg: TLMessage, user: UserManager, client: Telegr
     @Throws(RpcErrorException::class, IOException::class, TimeoutException::class)
     override fun download() {
         if (doc != null) {
-            DownloadManager.downloadFile(client, targetPathAndFilename, size, doc!!.getDcId(), doc!!.getId(), doc!!.getAccessHash())
+            DownloadManager.downloadFile(targetPathAndFilename, size, doc!!.getDcId(), doc!!.getId(), doc!!.getAccessHash())
         }
     }
 }

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

@@ -44,7 +44,7 @@ import org.apache.commons.io.FileUtils
 object FileManagerFactory {
     fun getFileManager(m: TLMessage?, u: UserManager, c: TelegramClient): AbstractMediaFileManager? {
         if (m == null) return null
-        val media = m!!.getMedia() ?: return null
+        val media = m.getMedia() ?: return null
 
         if (media is TLMessageMediaPhoto) {
             return PhotoFileManager(m, u, c)

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

@@ -50,7 +50,7 @@ class GeoFileManager(msg: TLMessage, user: UserManager, client: TelegramClient)
     override val size: Int
         get() {
             val f = File(targetPathAndFilename)
-            return if (f.isFile()) (f.length() as Int) else 100000
+            return if (f.isFile()) f.length().toInt() else 100000
         }
 
     override val extension: String
@@ -63,7 +63,7 @@ class GeoFileManager(msg: TLMessage, user: UserManager, client: TelegramClient)
     init {
         val g = (msg.getMedia() as TLMessageMediaGeo).getGeo()
         if (g is TLGeoPoint) {
-            this.geo = g as TLGeoPoint
+            this.geo = g
         } else if (g is TLGeoPointEmpty) {
             this.isEmpty = true
         } else {

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

@@ -55,14 +55,13 @@ class PhotoFileManager(msg: TLMessage, user: UserManager, client: TelegramClient
     init {
         val p = (msg.getMedia() as TLMessageMediaPhoto).getPhoto()
         if (p is TLPhoto) {
-            this.photo = p as TLPhoto
+            this.photo = p
 
             var biggest: TLPhotoSize? = null
-            for (s in photo!!.getSizes())
+            for (s in photo.getSizes())
                 if (s is TLPhotoSize) {
-                    val size = s as TLPhotoSize
+                    if (biggest == null || s.getW() > biggest.getW() && s.getH() > biggest.getH()) {
-                    if (biggest == null || size.getW() > biggest!!.getW() && size.getH() > biggest!!.getH()) {
+                        biggest = s
-                        biggest = size
                     }
                 }
             if (biggest == null) {
@@ -81,6 +80,6 @@ class PhotoFileManager(msg: TLMessage, user: UserManager, client: TelegramClient
     override fun download() {
         if (isEmpty) return
         val loc = photo_size.getLocation() as TLFileLocation
-        DownloadManager.downloadFile(client, targetPathAndFilename, size, loc.getDcId(), loc.getVolumeId(), loc.getLocalId(), loc.getSecret())
+        DownloadManager.downloadFile(targetPathAndFilename, size, loc.getDcId(), loc.getVolumeId(), loc.getLocalId(), loc.getSecret())
     }
 }

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

@@ -59,18 +59,19 @@ class StickerFileManager(msg: TLMessage, user: UserManager, client: TelegramClie
             var sticker: TLDocumentAttributeSticker? = null
             for (attr in doc!!.getAttributes()) {
                 if (attr is TLDocumentAttributeSticker) {
-                    sticker = attr as TLDocumentAttributeSticker
+                    sticker = attr
                 }
             }
 
             val file = StringBuilder()
-            if (sticker!!.getStickerset() is TLInputStickerSetShortName) {
+            val set = sticker!!.getStickerset()
-                file.append((sticker!!.getStickerset() as TLInputStickerSetShortName).getShortName())
+            if (set is TLInputStickerSetShortName) {
-            } else if (sticker!!.getStickerset() is TLInputStickerSetID) {
+                file.append(set.getShortName())
-                file.append((sticker!!.getStickerset() as TLInputStickerSetID).getId())
+            } else if (set is TLInputStickerSetID) {
+                file.append(set.getId())
             }
             file.append("_")
-            file.append(sticker!!.getAlt().hashCode())
+            file.append(sticker.getAlt().hashCode())
             return file.toString()
         }