Q:

Bukkit Java Coding, night checker

I want to make a plugin that fills a location on my map at a certain time. But when I try to use the event WorldEvent, it does not work; it says 
Unable to find handler list for event org.bukkit.event.world.WorldEvent

This is what I have so far:
  @EventHandler
    public void onTimeNight(WorldEvent e) {
        long time = e.getWorld().getTime();
        // -469 78 418
        // -469 30 433
        if (time == 13000) {
            int x = -469;
            for (int y = 30; y < 80; y++) {
                for (int z = 402; z < 418; z++) {
                    Location location = new Location(e.getWorld(), x, y, z);
                    location.getBlock().setType(Material.BRICK);

                }
            }
        }

    }

A:

WorldEvent is not an event that is being triggered. WorldEvent is just an abstract class that represents WorldEvents.
Use ChunkLoadEvent, ChunkPopulateEvent, ChunkUnloadEvent, PortalCreateEvent, SpawnChangeEvent, StructureGrowEvent, WorldInitEvent, WorldLoadEvent, WorldSaveEvent, WorldUnloadEvent as events. Read more about these at Spigot Docs https://hub.spigotmc.org/javadocs/spigot/org/bukkit/event/world/package-summary.html
For what you want to do, you need to create task that will check time every tick. Checking something every tick shouldn't be too inefficient if you just check world time.
Example below only shows how to make task using innerclass. It is the best to create class and exetend it with BukkitRunnable and do the same code as below in it.
public void scheduleTimer(Plugin plugin, final World world) {
    plugin.getServer().getScheduler().scheduleSyncRepeatingTask(plugin, new Runnable() {
        public void run() {
            long time = world.getTime();
            // -469 78 418
            // -469 30 433
            if (time == 13000) {
                int x = -469;
                for (int y = 30; y < 80; y++) {
                    for (int z = 402; z < 418; z++) {
                        Location location = new Location(e.getWorld(), x, y, z);
                        location.getBlock().setType(Material.BRICK);

                    }
                }
            }
        }
    }, 1, 1);
}

