// SubscribeCallback is an Abstract Java class. It requires that you implement all Abstract methods of the parent class even if you don't need all the handler methods.

pubnub.addListener(new SubscribeCallback() {
    // PubNub status
    @Override
    public void status(PubNub pubnub, PNStatus status) {
        switch (status.getOperation()) {
            // combine unsubscribe and subscribe handling for ease of use
            case PNSubscribeOperation:
            case PNUnsubscribeOperation:
                // Note: subscribe statuses never have traditional errors,
                // just categories to represent different issues or successes
                // that occur as part of subscribe
                switch (status.getCategory()) {
                    case PNConnectedCategory:
                        // No error or issue whatsoever.
                    case PNReconnectedCategory:
                        // Subscribe temporarily failed but reconnected.
                        // There is no longer any issue.
                    case PNDisconnectedCategory:
                        // No error in unsubscribing from everything.
                    case PNUnexpectedDisconnectCategory:
                        // Usually an issue with the internet connection.
                        // This is an error: handle appropriately.
                    case PNAccessDeniedCategory:
                        // PAM does not allow this client to subscribe to this
                        // channel and channel group configuration. This is
                        // another explicit error.
                    default:
                        // You can directly specify more errors by creating
                        // explicit cases for other error categories of
                        // `PNStatusCategory` such as `PNTimeoutCategory` or
                        // `PNMalformedFilterExpressionCategory` or
                        // `PNDecryptionErrorCategory`.
                }

            case PNHeartbeatOperation:
                // Heartbeat operations can in fact have errors,
                // so it's important to check first for an error.
                // For more information on how to configure heartbeat notifications
                // through the status PNObjectEventListener callback, refer to
                // /docs/android-java/api-reference-configuration#configuration_basic_usage
                if (status.isError()) {
                    // There was an error with the heartbeat operation, handle here
                } else {
                    // heartbeat operation was successful
                }
            default: {
                // Encountered unknown status type
            }
        }
    }

    // Messages
    @Override
    public void message(PubNub pubnub, PNMessageResult message) {
        String messagePublisher = message.getPublisher();
        System.out.println("Message publisher: " + messagePublisher);
        System.out.println("Message Payload: " + message.getMessage());
        System.out.println("Message Subscription: " + message.getSubscription());
        System.out.println("Message Channel: " + message.getChannel());
        System.out.println("Message timetoken: " + message.getTimetoken());
    }

    // Presence
    @Override
    public void presence(@NotNull PubNub pubnub, @NotNull PNPresenceEventResult presence) {
        System.out.println("Presence Event: " + presence.getEvent());
        // Can be join, leave, state-change or timeout

        System.out.println("Presence Channel: " + presence.getChannel());
        // The channel to which the message was published

        System.out.println("Presence Occupancy: " + presence.getOccupancy());
        // Number of users subscribed to the channel

        System.out.println("Presence State: " + presence.getState());
        // User state

        System.out.println("Presence UUID: " + presence.getUuid());
        // UUID to which this event is related

        presence.getJoin();
        // List of users that have joined the channel (if event is 'interval')

        presence.getLeave();
        // List of users that have left the channel (if event is 'interval')

        presence.getTimeout();
        // List of users that have timed-out off the channel (if event is 'interval')

        presence.getHereNowRefresh();
        // Indicates to the client that it should call 'hereNow()' to get the
        // complete list of users present in the channel.
    }

    // Signals
    @Override
    public void signal(PubNub pubnub, PNSignalResult pnSignalResult) {
        System.out.println("Signal publisher: " + signal.getPublisher());
        System.out.println("Signal payload: " + signal.getMessage());
        System.out.println("Signal subscription: " + signal.getSubscription());
        System.out.println("Signal channel: " + signal.getChannel());
        System.out.println("Signal timetoken: " + signal.getTimetoken());
    }

    // Message actions
    @Override
    public void messageAction(PubNub pubnub, PNMessageActionResult pnActionResult) {
        PNMessageAction pnMessageAction = pnActionResult.getAction();
        System.out.println("Message action type: " + pnMessageAction.getType());
        System.out.println("Message action value: " + pnMessageAction.getValue());
        System.out.println("Message action uuid: " + pnMessageAction.getUuid());
        System.out.println("Message action actionTimetoken: " + pnMessageAction.getActionTimetoken());
        System.out.println("Message action messageTimetoken: " + pnMessageAction.getMessageTimetoken());]
        System.out.println("Message action subscription: " + pnActionResult.getSubscription());
        System.out.println("Message action channel: " + pnActionResult.getChannel());
        System.out.println("Message action timetoken: " + pnActionResult.getTimetoken());
    }

    // Files
    @Override
    public void file(PubNub pubnub, PNFileEventResult pnFileEventResult) {
        System.out.println("File channel: " + pnFileEventResult.getChannel());
        System.out.println("File publisher: " + pnFileEventResult.getPublisher());
        System.out.println("File message: " + pnFileEventResult.getMessage());
        System.out.println("File timetoken: " + pnFileEventResult.getTimetoken());
        System.out.println("File file.id: " + pnFileEventResult.getFile().getId());
        System.out.println("File file.name: " + pnFileEventResult.getFile().getName());
        System.out.println("File file.url: " + pnFileEventResult.getFile().getUrl());
    }
});

pubnub.publish().channel(channelName)
  .message(messageJsonObject)
  .async((result, publishStatus) -> {
    if (!publishStatus.isError()) {
        // Message successfully published to specified channel.
    } else { // Request processing failed.
        // Handle message publish error
        // Check 'category' property to find out
        // issues because of which the request failed.
        // Request can be resent using: [status retry];
    }
});