Authentication Error while using google SpreadSheet API

Question

I have below class

import java.net.URL;

import com.google.gdata.client.spreadsheet.CellQuery;
import com.google.gdata.client.spreadsheet.SpreadsheetService;
import com.google.gdata.data.spreadsheet.CellEntry;
import com.google.gdata.data.spreadsheet.CellFeed;
import com.google.gdata.data.spreadsheet.SpreadsheetEntry;
import com.google.gdata.data.spreadsheet.WorksheetEntry;

public class ExpressionExample {

    public static final String GOOGLE_ACCOUNT_USERNAME = "********";

    public static final String GOOGLE_ACCOUNT_PASSWORD = "*********";

    private static URL cellFeedUrl;

    public static final String SPREADSHEET_URL = "https://spreadsheets.google.com/feeds/spreadsheets/1QWX-zOkBe36M7oC9sn6z8ZuccGt7Wg-IFwtynn379kM";

    public static void main(String[] args) throws Exception {

        SpreadsheetService service = new SpreadsheetService(
                "");

        service.setUserCredentials(GOOGLE_ACCOUNT_USERNAME,
                GOOGLE_ACCOUNT_PASSWORD);

        URL metafeedUrl = new URL(SPREADSHEET_URL);

        SpreadsheetEntry spreadsheet = service.getEntry(metafeedUrl,
                SpreadsheetEntry.class);

        WorksheetEntry sheet = ((WorksheetEntry) spreadsheet.getWorksheets()
                .get(0));

        cellFeedUrl = spreadsheet.getWorksheets().get(0).getCellFeedUrl();

        CellEntry cellA1 = new CellEntry(1, 1, "3");
        CellEntry cellB1 = new CellEntry(1, 2, "high mech");

        String line = "=IF(A1<5,IF(B1={\"high mech\",\"low mech\",\"mid mech\"},10,IF(B1=\"electronic\",20,0)),IF(A1>=5,IF(B1=\"electronic\",40,0),0)) ";
        CellEntry cellc1 = new CellEntry(1, 3, line);

        service.insert(cellFeedUrl, cellA1);
        service.insert(cellFeedUrl, cellB1);
        service.insert(cellFeedUrl, cellc1);

        ExpressionExample e = new ExpressionExample();
        e.printCell(cellA1);
        e.printCell(cellB1);
        e.printCell(cellc1);

        CellQuery query = new CellQuery(cellFeedUrl);
        query.setMinimumRow(1);
        query.setMaximumRow(1);
        query.setMinimumCol(3);
        query.setMaximumCol(3);

         CellFeed feed = service.query(query, CellFeed.class);

         System.out.println(feed.getEntries().indexOf(cellc1));
         for (CellEntry entry : feed.getEntries()) {
             e.printCell(entry);
            }
    }

    public void printCell(CellEntry cell) {
        //String shortId = cell.getId().substring(cell.getId().lastIndexOf('/') + 1);
        System.out.println(" -- Cell("+ "/" +  ") formula(" + cell.getCell().getInputValue() + ") numeric("
            + cell.getCell().getNumericValue() + ") value("
            + cell.getCell().getValue() + ")");
      }
}

When I try to login through the credentials, google lets me login. but when I use this program, I am getting Authentication exception.

It was working fine the day before but suddenly stopped working.

any help will be appreciated.