Message Events

Message-related events in JDA including messages, reactions, and polls

Overview

Message events are fired when messages are created, updated, deleted, or when users interact with them through reactions or polls.

Required Intents

Message events require the following Gateway Intents:

• GUILD_MESSAGES - For messages in guild channels
• DIRECT_MESSAGES - For messages in DMs
• MESSAGE_CONTENT - For accessing message content (privileged)

JDA jda = JDABuilder.createDefault(token)
    .enableIntents(
        GatewayIntent.GUILD_MESSAGES,
        GatewayIntent.DIRECT_MESSAGES,
        GatewayIntent.MESSAGE_CONTENT
    )
    .build();

Message Lifecycle Events

MessageReceivedEvent

Fired when a message is sent in a channel your bot has access to.

Package: net.dv8tion.jda.api.events.message

@Override
public void onMessageReceived(MessageReceivedEvent event) {
    Message message = event.getMessage();
    User author = event.getAuthor();
    MessageChannel channel = event.getChannel();
    
    // Check if message is from a bot
    if (event.isWebhookMessage()) {
        System.out.println("Message from webhook");
        return;
    }
    
    // Get member (null in DMs)
    Member member = event.getMember();
    if (member != null) {
        System.out.println("Guild message from: " + member.getEffectiveName());
    }
    
    // Access message content
    String content = message.getContentRaw();
    System.out.println("Message: " + content);
}

Key Methods:

• getMessage() - The message that was received
• getAuthor() - The user who sent the message
• getMember() - The member who sent the message (null in DMs)
• getChannel() - The channel where the message was sent
• isWebhookMessage() - Whether the message was sent by a webhook

MessageUpdateEvent

Fired when a message is edited.

Package: net.dv8tion.jda.api.events.message

@Override
public void onMessageUpdate(MessageUpdateEvent event) {
    Message message = event.getMessage();
    
    System.out.println("Message updated: " + event.getMessageId());
    System.out.println("New content: " + message.getContentRaw());
    
    // Check if message was edited
    if (message.isEdited()) {
        System.out.println("Edited at: " + message.getTimeEdited());
    }
}

Key Methods:

• getMessage() - The updated message
• getMessageId() / getMessageIdLong() - The message ID
• getChannel() - The channel containing the message

MessageDeleteEvent

Fired when a message is deleted.

Package: net.dv8tion.jda.api.events.message

@Override
public void onMessageDelete(MessageDeleteEvent event) {
    long messageId = event.getMessageIdLong();
    MessageChannel channel = event.getChannel();
    
    System.out.println("Message " + messageId + " deleted in " + channel.getName());
}

Note: This event only provides the message ID, not the full message object, as the message has been deleted.

Key Methods:

• getMessageId() / getMessageIdLong() - The deleted message ID
• getChannel() - The channel where the message was deleted

MessageBulkDeleteEvent

Fired when multiple messages are deleted at once (bulk delete).

Package: net.dv8tion.jda.api.events.message

@Override
public void onMessageBulkDelete(MessageBulkDeleteEvent event) {
    List<String> messageIds = event.getMessageIds();
    int count = event.getMessageIds().size();
    
    System.out.println(count + " messages were bulk deleted");
    System.out.println("Deleted IDs: " + messageIds);
}

Key Methods:

• getMessageIds() - List of deleted message IDs
• getChannel() - The channel where messages were deleted

Reaction Events

Reaction events fire when users add or remove reactions from messages.

MessageReactionAddEvent

Fired when a user adds a reaction to a message.

Package: net.dv8tion.jda.api.events.message.react

@Override
public void onMessageReactionAdd(MessageReactionAddEvent event) {
    User user = event.getUser();
    MessageReaction.ReactionEmoji emoji = event.getReaction().getEmoji();
    
    // Handle custom emoji
    if (emoji.getType() == MessageReaction.ReactionEmoji.Type.CUSTOM) {
        System.out.println("Custom emoji: " + emoji.getName());
    } else {
        // Unicode emoji
        System.out.println("Unicode emoji: " + emoji.getAsReactionCode());
    }
    
    // Retrieve the message
    event.retrieveMessage().queue(message -> {
        System.out.println("Reaction added to: " + message.getContentRaw());
    });
}

Key Methods:

• getUser() - The user who added the reaction
• getUserIdLong() - The user ID
• getReaction() - The reaction that was added
• getEmoji() - The emoji of the reaction
• retrieveMessage() - Retrieves the full message (RestAction)

MessageReactionRemoveEvent

Fired when a user removes a reaction from a message.

Package: net.dv8tion.jda.api.events.message.react

@Override
public void onMessageReactionRemove(MessageReactionRemoveEvent event) {
    User user = event.getUser();
    MessageReaction.ReactionEmoji emoji = event.getReaction().getEmoji();
    
    System.out.println(user.getName() + " removed reaction: " + emoji.getName());
}

MessageReactionRemoveAllEvent

Fired when all reactions are removed from a message.

Package: net.dv8tion.jda.api.events.message.react

@Override
public void onMessageReactionRemoveAll(MessageReactionRemoveAllEvent event) {
    long messageId = event.getMessageIdLong();
    System.out.println("All reactions removed from message: " + messageId);
}

MessageReactionRemoveEmojiEvent

Fired when all reactions of a specific emoji are removed from a message.

Package: net.dv8tion.jda.api.events.message.react

@Override
public void onMessageReactionRemoveEmoji(MessageReactionRemoveEmojiEvent event) {
    MessageReaction.ReactionEmoji emoji = event.getReaction().getEmoji();
    long count = event.getReaction().getCount();
    
    System.out.println("All " + emoji.getName() + " reactions removed (" + count + ")");
}

Poll Events

Poll events fire when users vote on message polls.

MessagePollVoteAddEvent

Fired when a user votes in a poll.

Package: net.dv8tion.jda.api.events.message.poll

@Override
public void onMessagePollVoteAdd(MessagePollVoteAddEvent event) {
    long answerId = event.getAnswerId();
    User user = event.getUser();
    
    System.out.println(user.getName() + " voted for answer: " + answerId);
    
    // Retrieve the message to get poll details
    event.retrieveMessage().queue(message -> {
        MessagePoll poll = message.getPoll();
        if (poll != null) {
            System.out.println("Poll: " + poll.getQuestion().getText());
        }
    });
}

Key Methods:

• getAnswerId() - The ID of the poll answer
• getUser() - The user who voted
• getMessageIdLong() - The message containing the poll
• retrieveMessage() - Retrieves the full message

MessagePollVoteRemoveEvent

Fired when a user removes their vote from a poll.

Package: net.dv8tion.jda.api.events.message.poll

@Override
public void onMessagePollVoteRemove(MessagePollVoteRemoveEvent event) {
    long answerId = event.getAnswerId();
    User user = event.getUser();
    
    System.out.println(user.getName() + " removed vote from answer: " + answerId);
}

Generic Message Events

GenericMessageEvent

Base event for all message-related events.

@Override
public void onGenericMessage(GenericMessageEvent event) {
    // Fires for all message events
    System.out.println("Message event type: " + event.getClass().getSimpleName());
}

GenericMessageReactionEvent

Base event for all reaction-related events.

@Override
public void onGenericMessageReaction(GenericMessageReactionEvent event) {
    // Fires for all reaction events
    MessageReaction.ReactionEmoji emoji = event.getReaction().getEmoji();
    System.out.println("Reaction event for: " + emoji.getName());
}

GenericMessagePollVoteEvent

Base event for all poll vote events.

@Override
public void onGenericMessagePollVote(GenericMessagePollVoteEvent event) {
    // Fires for all poll vote events
    System.out.println("Poll vote event for answer: " + event.getAnswerId());
}

Example: Command Handler

Here’s a complete example of a simple command handler using message events:

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

public class CommandHandler extends ListenerAdapter {
    private static final String PREFIX = "!";
    
    @Override
    public void onMessageReceived(MessageReceivedEvent event) {
        // Ignore bots
        if (event.getAuthor().isBot()) return;
        
        String content = event.getMessage().getContentRaw();
        
        // Check for prefix
        if (!content.startsWith(PREFIX)) return;
        
        // Parse command
        String[] parts = content.substring(PREFIX.length()).split("\\s+");
        String command = parts[0].toLowerCase();
        
        switch (command) {
            case "ping":
                event.getChannel().sendMessage("Pong!").queue();
                break;
                
            case "info":
                event.getChannel().sendMessage(
                    "Message from: " + event.getAuthor().getAsTag() +
                    "\nChannel: " + event.getChannel().getName()
                ).queue();
                break;
                
            case "react":
                event.getMessage().addReaction(event.getJDA()
                    .getEmojiById("123456789")).queue();
                break;
        }
    }
}

Tips and Best Practices

1. Cache Messages - Message objects are not cached by default. Use enableCache(CacheFlag.MESSAGE) if you need to access messages later

2. Check Permissions - Always verify your bot has permission to send messages before responding:

   if (event.getGuild().getSelfMember().hasPermission(event.getChannel(), Permission.MESSAGE_SEND)) {
       // Send message
   }
   

3. Handle Rate Limits - Use .queue() instead of .complete() to avoid blocking and handle rate limits gracefully

4. Filter Webhooks - Use isWebhookMessage() to filter out webhook messages if needed

5. DM vs Guild - Check if getMember() is null to determine if a message is from a DM