Backwards-compatible Server::getOnlinePlayers::size

BukkitGetOnlinePlayerCount.java

private int getOnlinePlayers() {
    try {
        Method onlinePlayerMethod = Server.class.getMethod("getOnlinePlayers");
        if (onlinePlayerMethod.getReturnType().equals(Collection.class)) {
            return ((Collection<?>) onlinePlayerMethod.invoke(Bukkit.getServer())).size();
        } else {
            return ((Player[]) onlinePlayerMethod.invoke(Bukkit.getServer())).length;
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    
    return 0;
}