Fix Seat problem

src/de/steamwar/spectatesystem/listener/PlayerSeatListener.java

@@ -20,6 +20,8 @@
 package de.steamwar.spectatesystem.listener;
 
 import org.bukkit.GameMode;
+import org.bukkit.Location;
+import org.bukkit.Material;
 import org.bukkit.block.data.Bisected;
 import org.bukkit.block.data.type.Stairs;
 import org.bukkit.entity.AbstractArrow;
@@ -49,7 +51,11 @@ public class PlayerSeatListener extends BasicListener {
         if(event.getPlayer().isInsideVehicle())
             event.getPlayer().getVehicle().remove();
 
-        Arrow arrow = (Arrow) event.getPlayer().getWorld().spawnEntity(event.getClickedBlock().getLocation().add(0.5, 0, 0.5), EntityType.ARROW);
+        Location location = event.getClickedBlock().getLocation();
+        if (location.getWorld().getBlockAt(location.getBlockX(), location.getBlockY() + 1, location.getBlockZ()).getType() == Material.AIR)
+            return;
+
+        Arrow arrow = (Arrow) event.getPlayer().getWorld().spawnEntity(location.add(0.5, 0, 0.5), EntityType.ARROW);
         arrow.setGravity(false);
         arrow.setPickupStatus(AbstractArrow.PickupStatus.DISALLOWED);
         arrow.addPassenger(event.getPlayer());