notify-on-start/src/main/java/moe/sob/ServerUtils.java

package moe.sob;

import org.bukkit.Bukkit;
import org.bukkit.Server;

import java.net.InetSocketAddress;
import java.net.Socket;

public class ServerUtils {
    public static int port = 25565;
    public static String address_fallback = "localhost";
    public static String webhook_notify = Main.getNotifyWebhook();
    public static String webhook_messages = Main.getPublicMessageWebhook();
    public static String address = Utils.getServerHostPublicIP();

    public static boolean serverIsUp(String serverAddress, Integer serverPort) {
        try {
            Server server = Bukkit.getServer();
            Socket s = new Socket();
            s.connect(new InetSocketAddress(serverAddress, Integer.parseInt(serverPort.toString())), 15);
            s.close();
            System.out.println("Server is online. Test notifying by sending a message to your webhook... (Pinged " + serverAddress + ":" + server.getPort() + ")");
            return true;
        } catch (Exception e) {
            System.out.println("Server is inactive. Pinging fallback address...");
            try {
                Server server = Bukkit.getServer();
                Socket s = new Socket();
                s.connect(new InetSocketAddress(address_fallback, Integer.parseInt(serverPort.toString())), 15);
                s.close();
                System.out.println("Server is online. Sending message to webhook_notify... (Pinged " + Utils.getServerHostPublicIP() + ":" + server.getPort() + ")");
                return true;
            } catch (Exception err) {
                System.out.println("Fallback address is inactive. No longer pinging...");
            }
            return false;
        }
    }

}