I have imported a project from a book on Android development and I am currently getting warnings icons appearing next to a number of imports at the start of my project. When I hover over the warning icon the message that appears is as follows...

"The import java.io.IOException is never used"

I received these warning before on another project and when I imported a the necessary library the warning icons disappeared. My problem is that I do not know which library to import to resolve the warning symbol next to the following statements in my .java file...

```
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.text.ParseException;
import java.util.GregorianCalendar;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

```