[Su37Erich]

Thanks for your answer, I'll be trying to find out what's happening.
Furthermore, I have tried to change the default message but I can't figure how, here is what I tried:

Код:

public final PlayerCommandManager.UsageMessageSupplier CMESSAGE = (player, prefix, command) ->
    {
        StringBuilder stringBuilder = new StringBuilder("» Correct usage: " + prefix + command.getCommand());
        if(command.getParameters().length > 0) {
            for(int i = 0; i < command.getParameters().length; i++) {
                stringBuilder.append(" <").append(command.getParameters()[i].name()).append(">");
            }
        }
        if(command.getHelpMessage() != null)
            stringBuilder.append(" - ").append(command.getHelpMessage());
        return stringBuilder.toString();
    };

Код:

commandManager.setUsageMessageSupplier(CMESSAGE);

Another try:

Код:

commandManager.setUsageMessageSupplier((player, prefix, command) ->
        {
            StringBuilder stringBuilder = new StringBuilder("» Correct usage: " + prefix + command.getCommand());
            if(command.getParameters().length > 0) {
                for(int i = 0; i < command.getParameters().length; i++) {
                    stringBuilder.append(" <").append(command.getParameters()[i].name()).append(">");
                }
            }
            if(command.getHelpMessage() != null)
                stringBuilder.append(" - ").append(command.getHelpMessage());
            return stringBuilder.toString();
        });

But I always get something like this:
java.lang.AbstractMethodError: dev.acesamp.EventManager$$Lambda$1548/21424390.get(Lnet/gtaun/shoebill/object/Player;Ljava/lang/String;Ljava/lang/String;[Ljava/lang/String;Ljava/lang/StringLjava/lang/String;