Вопрос Проблема с кодом

[Pavlikus]

При вызове команды /blueprint list появляется ошибка:

Спойлер: Вывод консоли

[19:19:42 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'blueprints' in plugin Rustified v${project.version}
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot.jar:git-Paper-1618]
at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:152) ~[spigot.jar:git-Paper-1618]
at org.bukkit.craftbukkit.v1_12_R1.CraftServer.dispatchCommand(CraftServer.java:685) ~[spigot.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.PlayerConnection.handleCommand(PlayerConnection.java:1492) ~[spigot.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.PlayerConnection.a(PlayerConnection.java:1297) ~[spigot.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.PacketPlayInChat.a(PacketPlayInChat.java:45) ~[spigot.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.PacketPlayInChat.a(PacketPlayInChat.java:5) ~[spigot.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.PlayerConnectionUtils.lambda$ensureMainThread$0(PlayerConnectionUtils.java:14) ~[spigot.jar:git-Paper-1618]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_261]
at net.minecraft.server.v1_12_R1.SystemUtils.a(SourceFile:46) ~[spigot.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:850) ~[spigot.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:423) ~[spigot.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:774) ~[spigot.jar:git-Paper-1618]
at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:666) ~[spigot.jar:git-Paper-1618]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_261]
Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: 20
at java.lang.String.substring(Unknown Source) ~[?:1.8.0_261]
at me.perotin.rustified.commands.BluePrintCommand.onCommand(BluePrintCommand.java:54) ~[?:?]
at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot.jar:git-Paper-1618]
... 15 more

Спойлер: Код

package me.perotin.rustified.commands;

import me.perotin.rustified.Rustified;
import me.perotin.rustified.files.RustFile;
import me.perotin.rustified.objects.BluePrint;
import me.perotin.rustified.objects.BluePrintData;
import me.perotin.rustified.objects.RustifiedPlayer;
import me.perotin.rustified.utils.Messages;
import net.md_5.bungee.api.chat.ClickEvent;
import net.md_5.bungee.api.chat.ComponentBuilder;
import net.md_5.bungee.api.chat.HoverEvent;
import net.md_5.bungee.api.chat.TextComponent;
import org.bukkit.ChatColor;
import org.bukkit.command.Command;
import org.bukkit.command.CommandExecutor;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.scheduler.BukkitRunnable;
import java.util.List;
import java.util.stream.Collectors;

/* Created by Perotin on 4/28/19 */
public class BluePrintCommand implements CommandExecutor {

private Rustified plugin;

public BluePrintCommand(Rustified rustified) {
this.plugin = rustified;
}

@Override
public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
if (sender instanceof Player) {
Player player = (Player) sender;
RustifiedPlayer rustifiedPlayer = Rustified.getPlayerObjectFor(player);
RustFile messages = new RustFile(RustFile.RustFileType.MESSAGES);
if (sender.hasPermission("rustified.blueprint")) {
if(args.length == 0) {
sender.sendMessage(ChatColor.GREEN + "---------------- " + ChatColor.AQUA + "Rustified " + ChatColor.GREEN + "----------------");
sender.sendMessage(Messages.getMessage("click-msg-copy"));
Messages.sendMessageTextComponent("blueprint-help", player);
Messages.sendMessageTextComponent("blueprint-list", player);
} else if(args.length == 1){
String arg1 = args[0];
if(arg1.equalsIgnoreCase("list")){
//display list
List<String> bluePrints = rustifiedPlayer.getBlueprints().stream().map(bp -> bp.getMaterial().toString()).collect(Collectors.toList());
String message = messages.getString("blueprint-list-message");
message = message.replace("$prefix$", messages.getString("prefix")).replace("$amount$", bluePrints.size()+"");
String holder = "";
for(String print : bluePrints){
holder = print +", ";
}
holder = holder.trim().substring(1, holder.length());
player.sendMessage(message.replace("$list$", holder));
} else if(arg1.equalsIgnoreCase("help")){
List<String> helpMessages = messages.getConfiguration().getStringList("blueprint-help-message");
int counter = 0;
for(String s : helpMessages){
if(counter == 0){
counter++;
player.sendMessage(ChatColor.translateAlternateColorCodes('&', s));
} else {
new BukkitRunnable(){
@Override
public void run(){
player.sendMessage(ChatColor.translateAlternateColorCodes('&', s));

}
}.runTaskLater(plugin, 20*3);
}

}
} else if(arg1.equalsIgnoreCase("info")){
// display GUI with details about server
BluePrintData.getSingleton().showInfoInventory(player);
}
}



} else {
Messages.sendMessage("no-permission", player);
}
return true;
}
return true;
}
}

 

[Xezard]

me.perotin.rustified.commands.BluePrintCommand.onCommand(BluePrintCommand.java:54) ~[?:?] - причина.

А это, полагаю, проблемное место:
holder = holder.trim().substring(1, holder.length());