Friend finder main class

FriendFinder.java

package twitter.friends;

import java.io.IOException;
import java.sql.SQLException;
import java.util.List;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;

import db.DBResources;
import twitter4j.Twitter;
import twitter4j.TwitterFactory;
import utils.FileUtils;

public class FriendFinder {

	private Twitter twitter;
	
	public FriendFinder() throws SQLException {
    		this.twitter = new TwitterFactory().getInstance();
	}
	public void find(List<Long> userIds) throws InterruptedException, SQLException {
		BlockingQueue<Long> friendsLookupQueue = new LinkedBlockingQueue<>();
		BlockingQueue<Long> usersLookupQueue = new LinkedBlockingQueue<>();

		friendsLookupQueue.addAll(userIds);

		Thread friendsLookupThread = new Thread(new FriendsLookupRunnable(twitter, 
				friendsLookupQueue, usersLookupQueue));
		Thread usersLookupThread = new Thread(new UsersLookupRunnable(twitter, usersLookupQueue));
		
		friendsLookupThread.start();
		usersLookupThread.start();
		
	  	Runtime.getRuntime().addShutdownHook(new Thread(()->
		{
			friendsLookupThread.interrupt();
			usersLookupThread.interrupt();
			DBResources.getInstance().close();
		}));

		friendsLookupThread.join();
		usersLookupThread.join();
		
		DBResources.getInstance().close();
	}
	
	public static void main(String[] args) throws SQLException, InterruptedException, IOException {
		if (args.length < 2) {
			throw new IllegalArgumentException();
		}
    		String jdbcURL = args[0];
		String fileName = args[1];
		String sql = FileUtils.readFile(fileName);

		System.out.printf("PID is %d\n", ProcessHandle.current().pid());
		
		DBResources.newInstance(jdbcURL);
		DBResources.getInstance().getConnection().setAutoCommit(false);
		List<Long> userIds = FriendDAO.getUserIds(sql);
		
		FriendFinder friendFinder= new FriendFinder();
		friendFinder.find(userIds);
	}
}