!((CraftEntity)entity).getHandle().isSpectator() && ((CraftEntity)entity).getHandle().isPickable()

import org.bukkit.Bukkit;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.plugin.java.JavaPlugin;

public class Main extends JavaPlugin implements Listener {

    @Override
    public void onEnable() {
        getServer().getPluginManager().registerEvents(this, this);
    }

    @EventHandler
    public void onInteract(PlayerInteractEvent event) {
        Bukkit.broadcastMessage("Interaction: " + event.getAction());
    }
}