ArrowLandData

public class ArrowRemoval {
	public ArrowRemoval(){
		enable();
	}

	public static PriorityQueue<ArrowLandData> q = new PriorityQueue<ArrowLandData>();

	public void enable(){
		plugin.getInstance().getServer().getScheduler().scheduleSyncRepeatingTask(plugin.getInstance(), new Runnable(){

			@Override
			public void run() {
				ArrowLandData ald;
				while ((ald = q.peek()) != null && ald.isReady()) {
					q.poll().removeArrow();
				}

			}
		}, 100L, 100L);
	}

}

public class ArrowLandData {
	private Arrow arrow;
	private long landTime;
	public ArrowLandData(Arrow a) {
		arrow = a;
		landTime = System.currentTimeMillis();
	}
	public boolean isReady() {
		if (!arrow.isValid()) return true;
		return System.currentTimeMillis() > landTime + (1000 * 10);
	}
	public void removeArrow() {
		arrow.remove();
		arrow = null; // drop ref
	}
}