JDA (Java Discord API) is the standard wrapper for building Discord bots in Java, same Maven-based workflow as a Minecraft plugin, just a different API surface.

Create the bot application

1. Go to the Discord Developer Portal → New Application.
2. Bot tab → Reset Token (copy it somewhere safe, you can't view it again, only regenerate).
3. Under Privileged Gateway Intents, enable MESSAGE CONTENT INTENT if your bot reads message text (not needed for slash commands alone).
4. OAuth2 → URL Generator: check bot and applications.commands, pick permissions, use the generated URL to invite it to a test server.

Never commit your token to a public repo, load it from an environment variable or a git-ignored config file.

Maven setup

<dependency>
  <groupId>net.dv8tion</groupId>
  <artifactId>JDA</artifactId>
  <version>5.0.2</version>
</dependency>

Use the shade plugin exactly as in the Minecraft plugin setup, JDA isn't preinstalled anywhere, so unlike a Bukkit plugin, it needs to be bundled into your jar (don't mark it provided).

Minimal bot

import net.dv8tion.jda.api.JDABuilder;
import net.dv8tion.jda.api.JDA;
import net.dv8tion.jda.api.requests.GatewayIntent;

public class Bot {
    public static void main(String[] args) throws InterruptedException {
        String token = System.getenv("DISCORD_TOKEN");

        JDA jda = JDABuilder.createDefault(token)
            .enableIntents(GatewayIntent.MESSAGE_CONTENT)
            .addEventListeners(new MessageListener())
            .build();

        jda.awaitReady();
        System.out.println("Bot is online as " + jda.getSelfUser().getName());
    }
}

A basic listener

import net.dv8tion.jda.api.events.message.MessageReceivedEvent;
import net.dv8tion.jda.api.hooks.ListenerAdapter;

public class MessageListener extends ListenerAdapter {
    @Override
    public void onMessageReceived(MessageReceivedEvent event) {
        if (event.getAuthor().isBot()) return;
        if (event.getMessage().getContentRaw().equalsIgnoreCase("!ping")) {
            event.getChannel().sendMessage("Pong!").queue();
        }
    }
}

.queue() matters, JDA's REST calls are async; calling .complete() blocks the gateway thread and will eventually cause rate-limit and latency problems at any real scale.

Running it 24/7

A local JVM dies when your machine sleeps or reboots. For anything beyond testing:

• A small VPS (Java installed) running the jar under systemd or inside screen/tmux so it survives SSH disconnects.
• systemd service example (/etc/systemd/system/mybot.service):

[Unit]
Description=My Discord Bot
After=network.target

[Service]
ExecStart=/usr/bin/java -jar /opt/mybot/mybot.jar
Restart=on-failure
Environment=DISCORD_TOKEN=your_token_here
User=botuser

[Install]
WantedBy=multi-user.target

sudo systemctl enable --now mybot
sudo systemctl status mybot
journalctl -u mybot -f   # live logs

Next: Slash Commands, Buttons & Embeds.