DiscordRPC lib = DiscordRPC.INSTANCE;
String applicationId = "";
String steamId = "";
DiscordEventHandlers handlers = new DiscordEventHandlers();
handlers.ready = () -> System.out.println("Ready!");
lib.Discord_Initialize(applicationId, handlers, true, steamId);
DiscordRichPresence presence = new DiscordRichPresence();
presence.startTimestamp = System.currentTimeMillis() / 1000; // epoch second
presence.details = "Testing RPC";
lib.Discord_UpdatePresence(presence);
// in a worker thread
while (!Thread.currentThread().isInterrupted())
    lib.Discord_RunCallbacks();