title: Search file with query string does not work on google drive api
body: <p>Below is the code I am using to find list of files containing Volunteers.  </p>
  
  <pre><code>private static List&lt;File&gt; retrieveAllFiles(Drive service) throws IOException {
      List&lt;File&gt; result = new ArrayList&lt;File&gt;();
      Files.List request = service.files().list().setQ("Volunteers");
      System.out.println("Request size:" + request.size());
      do {
          try {
              FileList files = request.execute();
              System.out.println("Request files size:" + files.size());
              result.addAll(files.getItems());
              request.setPageToken(files.getNextPageToken());
          } catch (IOException e) {
              System.out.println("An error occurred: " + e);
              request.setPageToken(null);
          }
      } while (request.getPageToken() != null &amp;&amp;
               request.getPageToken().length() &gt; 0);
  
      return result;
  }
  </code></pre>
  
  <p>On execution it returns </p>
  
  <pre><code>[s~sakshumweb-hrd/3.368839385999923807].&lt;stdout&gt;: An error occurred: com.google.api.client.googleapis.json.GoogleJsonResponseException: 400 OK
  {
    "code" : 400,
    "errors" : [ {
      "domain" : "global",
      "location" : "q",
      "locationType" : "parameter",
      "message" : "Invalid Value",
      "reason" : "invalid"
    } ],
    "message" : "Invalid Value"
  }
  </code></pre>
  
  <p>What is wrong with it.</p>