How to use

setAvatar

method

in

net.dv8tion.jda.core.managers.AccountManager

/**
 * Sets the avatar for the currently logged in account
 *
 * <p><b>Client-Accounts ({@link net.dv8tion.jda.core.AccountType#CLIENT AccountType.CLIENT}) require the
 * current password to be updated. See {@link #setAvatar(net.dv8tion.jda.core.entities.Icon, String) #setAvatar(Icon, String)}</b>
 *
 * @param  avatar
 *         An {@link net.dv8tion.jda.core.entities.Icon Icon} instance representing
 *         the new Avatar for the current account, {@code null} to reset the avatar to the default avatar.
 *
 * @return AccountManager for chaining convenience
 */
@CheckReturnValue
public AccountManager setAvatar(Icon avatar)
{
  return setAvatar(avatar, null);
}

@Override
public void onCommand(User sender, GuildWrapper guild, TextChannel channel, Message message, String[] args, Member member) {
  if (args.length == 0) {
    if (!message.getAttachments().isEmpty()) {
      Message.Attachment attachment = message.getAttachments().get(0);
      try {
        sender.getJDA().getSelfUser().getManager().setAvatar(Icon.from(
            new URL(attachment.getUrl()).openStream()
        )).complete();
      } catch (IOException e) {
        channel.sendMessage("Failed to update avatar!! " + e).queue();
      }
      channel.sendMessage("Success!").queue();
    } else {
      channel.sendMessage("You must either attach an image or link to one!").queue();
    }
  } else {
    try {
      sender.getJDA().getSelfUser().getManager().setAvatar(Icon.from(
          new URL(args[0]).openStream()
      )).complete();
    } catch (IOException e) {
      channel.sendMessage("Failed to update avatar!! " + e).queue();
    }
    channel.sendMessage("Success!").queue();
  }
}

  @Override
  public String execute(DiscordBot bot, String[] args, MessageChannel channel, User author, Message inputMessage) {
    SimpleRank rank = bot.security.getSimpleRank(author);

    if (!rank.isAtLeast(SimpleRank.CREATOR)) {
      return Templates.no_permission.formatGuild(channel);
    }
    if (args.length <= 1) {
      try {
        Icon icon = Icon.from(Unirest.get(args[0]).asBinary().getBody());
        bot.queue.add(channel.getJDA().getSelfUser().getManager().setAvatar(icon));
      } catch (IOException | UnirestException e) {
        return "Error: " + e.getMessage();
      }
      return ":+1:";
    }
    return ":face_palm: I expected you to know how to use it";
  }
}

  @Override
  protected void execute(CommandEvent event) 
  {
    String url;
    if(event.getArgs().isEmpty())
      if(!event.getMessage().getAttachments().isEmpty() && event.getMessage().getAttachments().get(0).isImage())
        url = event.getMessage().getAttachments().get(0).getUrl();
      else
        url = null;
    else
      url = event.getArgs();
    InputStream s = OtherUtil.imageFromUrl(url);
    if(s==null)
    {
      event.reply(event.getClient().getError()+" Invalid or missing URL");
    }
    else
    {
      try {
      event.getSelfUser().getManager().setAvatar(Icon.from(s)).queue(
          v -> event.reply(event.getClient().getSuccess()+" Successfully changed avatar."), 
          t -> event.reply(event.getClient().getError()+" Failed to set avatar."));
      } catch(IOException e) {
        event.reply(event.getClient().getError()+" Could not load from provided URL.");
      }
    }
  }
}