Always specify Locale on toLowerCase and toUpperCase usages, fixes AuthMe not working correctly on machines with turkish locale. ('I'.toLowerCase() => 'ı')

src/main/java/fr/xephi/authme/command/executable/authme/AccountsCommand.java

@@ -10,6 +10,7 @@ import org.bukkit.command.CommandSender;
 
 import javax.inject.Inject;
 import java.util.List;
+import java.util.Locale;
 
 /**
  * Shows all accounts registered by the same IP address for the given player name or IP address.
@@ -44,7 +45,7 @@ public class AccountsCommand implements ExecutableCommand {
             });
         } else {
             bukkitService.runTaskAsynchronously(() -> {
-                PlayerAuth auth = dataSource.getAuth(playerName.toLowerCase());
+                PlayerAuth auth = dataSource.getAuth(playerName.toLowerCase(Locale.ROOT));
                 if (auth == null) {
                     commonService.send(sender, MessageKey.UNKNOWN_USER);
                     return;

src/main/java/fr/xephi/authme/command/executable/authme/ConverterCommand.java

@@ -22,6 +22,7 @@ import org.bukkit.command.CommandSender;
 
 import javax.inject.Inject;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 
 /**
@@ -71,7 +72,7 @@ public class ConverterCommand implements ExecutableCommand {
     private static Class<? extends Converter> getConverterClassFromArgs(List<String> arguments) {
         return arguments.isEmpty()
             ? null
-            : CONVERTERS.get(arguments.get(0).toLowerCase());
+            : CONVERTERS.get(arguments.get(0).toLowerCase(Locale.ROOT));
     }
 
     /**

src/main/java/fr/xephi/authme/command/executable/authme/PurgeBannedPlayersCommand.java

@@ -9,6 +9,7 @@ import org.bukkit.command.CommandSender;
 import javax.inject.Inject;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Locale;
 import java.util.Set;
 
 /**
@@ -29,7 +30,7 @@ public class PurgeBannedPlayersCommand implements ExecutableCommand {
         Set<OfflinePlayer> bannedPlayers = bukkitService.getBannedPlayers();
         Set<String> namedBanned = new HashSet<>(bannedPlayers.size());
         for (OfflinePlayer offlinePlayer : bannedPlayers) {
-            namedBanned.add(offlinePlayer.getName().toLowerCase());
+            namedBanned.add(offlinePlayer.getName().toLowerCase(Locale.ROOT));
         }
 
         purgeService.purgePlayers(sender, namedBanned, bannedPlayers.toArray(new OfflinePlayer[bannedPlayers.size()]));

src/main/java/fr/xephi/authme/command/executable/authme/PurgePlayerCommand.java

@@ -9,6 +9,7 @@ import org.bukkit.command.CommandSender;
 
 import javax.inject.Inject;
 import java.util.List;
+import java.util.Locale;
 
 import static java.util.Collections.singletonList;
 
@@ -36,7 +37,7 @@ public class PurgePlayerCommand implements ExecutableCommand {
     private void executeCommand(CommandSender sender, String name, String option) {
         if ("force".equals(option) || !dataSource.isAuthAvailable(name)) {
             OfflinePlayer offlinePlayer = bukkitService.getOfflinePlayer(name);
-            purgeExecutor.executePurge(singletonList(offlinePlayer), singletonList(name.toLowerCase()));
+            purgeExecutor.executePurge(singletonList(offlinePlayer), singletonList(name.toLowerCase(Locale.ROOT)));
             sender.sendMessage("Purged data for player " + name);
         } else {
             sender.sendMessage("This player is still registered! Are you sure you want to proceed? "

src/main/java/fr/xephi/authme/command/executable/authme/RegisterAdminCommand.java

@@ -17,6 +17,7 @@ import org.bukkit.entity.Player;
 
 import javax.inject.Inject;
 import java.util.List;
+import java.util.Locale;
 
 /**
  * Admin command to register a user.
@@ -45,7 +46,7 @@ public class RegisterAdminCommand implements ExecutableCommand {
         // Get the player name and password
         final String playerName = arguments.get(0);
         final String playerPass = arguments.get(1);
-        final String playerNameLowerCase = playerName.toLowerCase();
+        final String playerNameLowerCase = playerName.toLowerCase(Locale.ROOT);
 
         // Command logic
         ValidationResult passwordValidation = validationService.validatePassword(playerPass, playerName);

src/main/java/fr/xephi/authme/command/executable/authme/debug/DebugCommand.java

@@ -9,6 +9,7 @@ import org.bukkit.command.CommandSender;
 
 import javax.inject.Inject;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeMap;
@@ -45,7 +46,7 @@ public class DebugCommand implements ExecutableCommand {
         if (arguments.isEmpty()) {
             return null;
         }
-        return getSections().get(arguments.get(0).toLowerCase());
+        return getSections().get(arguments.get(0).toLowerCase(Locale.ROOT));
     }
 
     private void sendAvailableSections(CommandSender sender) {

src/main/java/fr/xephi/authme/command/executable/changepassword/ChangePasswordCommand.java

@@ -12,6 +12,7 @@ import org.bukkit.entity.Player;
 
 import javax.inject.Inject;
 import java.util.List;
+import java.util.Locale;
 
 /**
  * The command for a player to change his password with.
@@ -35,7 +36,7 @@ public class ChangePasswordCommand extends PlayerCommand {
 
     @Override
     public void runCommand(Player player, List<String> arguments) {
-        String name = player.getName().toLowerCase();
+        String name = player.getName().toLowerCase(Locale.ROOT);
 
         if (!playerCache.isAuthenticated(name)) {
             commonService.send(player, MessageKey.NOT_LOGGED_IN);