public class MyPlugin extends JavaPlugin implements Listener {
private final Map<UUID, Location> lastPlayerLocation = new HashMap<>();
@Override
public void onEnable() {
Bukkit.getPluginManager().registerEvents(this, this);
getCommand("back").setExecutor(this);
}
public Optional<Location> findLastPlayerLocation(Player player) {
Location location = lastPlayerLocation.get(player.getUniqueId());
return location == null ? Optional.empty() : Optional.of(location);
}...