URLConnection Reading in as null in java

Question

I'm a building a basic program to query Target's API with a store ID and Product ID which returns the aisle location. I think I'm using the URL constructor incorrectly, however (I've had trouble with it in the past and still don't fully understand them). Below is the code I have, redacted the API Key for obvious reasons. The URL I create is valid when put into a browser and no exceptions are thrown but at the the end when I print out the contents of the page it is null. What am I missing? Any help is really appreciated!

package productVerf;

import java.net.*;
import java.io.*;

public class Verify {
    public static void main(String args[]) {
        // first input is store id second input is product id
        String productID = args[0];
        String storeID = args[1];
        String file = "/v2/products/storeLocations?productId=" + productID
                + "&storeId=" + storeID
                + "&storeId=694&key=REDACTED";
        URL locQuery;
        URLConnection lqConection = null;
        try {

            locQuery = new URL("http", "api.target.com", file);
            lqConection = locQuery.openConnection();
        } catch (IOException e) {
            e.printStackTrace();
        }
        BufferedReader response;
        String responseString = "";
        try {
            response = new BufferedReader(new InputStreamReader(
                    lqConection.getInputStream()));
            while (response.readLine() != null) {
                responseString += response.readLine();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        System.out.println(responseString);

    }
}

Answer 1

Maybe you are reading only even lines

you are reading a line twice? (in while statement...), it looks you reads the first line which is dropped in while condition test. If your response contains only one line, nothing will be readed

use this:

String line;
while ((line=response.readLine()) != null) {
       responseString += line;
}