AutomaticLogDeleter/src/main/java/net/limework/automaticlogdeleter/AutomaticLogDeleter.java

package net.limework.automaticlogdeleter;

import org.bukkit.Bukkit;
import org.bukkit.configuration.file.FileConfiguration;
import org.bukkit.plugin.java.JavaPlugin;

import java.io.File;
import java.util.logging.Level;

public final class AutomaticLogDeleter extends JavaPlugin {

    @Override
    public void onEnable() {
        new Thread(() -> {
            this.saveDefaultConfig();
            deleteLogs();
        }).start();
    }

    @Override
    public void onDisable() {

        new Thread(() -> {
            FileConfiguration config = getConfig();
            if (config.getBoolean("also-delete-logs-on-shutdown")) {
                deleteLogs();
            }
        }).start();
    }

    public void deleteLogs() {
        File path = new File("logs");

        File[] files = path.listFiles();
        if (files == null) { return; }
        FileConfiguration config = getConfig();

        //maximum file age allowed

        long maxOldMillis = config.getLong("delete-logs-older-than-seconds") * 1000;

        for (File file : files) {
            if (file.isFile()) {
                if ((System.currentTimeMillis() - file.lastModified()) > maxOldMillis) {

                    if (!file.delete()) {
                        Bukkit.getLogger().log(Level.WARNING, "Failed to delete server log file! Are you sure the file permissions are correct?");
                    }
                }
            }
        }
    }
}