Query for list of files and folders in root directory

The root folder can also be addressed with a special alias named "root", so you can get all files and folders in the root with the following query:

https://www.googleapis.com/drive/v2/files?q='root' in parents

Remember to escape the URL if not using one of the client libraries (they automatically take care of it).

For more details about the search query language, check https://developers.google.com/drive/search-parameters

This code will display all files and folder of your ROOT DIRECTORY. just copy and paste this code and you will get all your root's file and folder.

 List<File> result = new ArrayList<File>();
    Files.List request = null;

    try {
          request = mService.files().list();
          FileList files = request.setQ("'root' in parents and trashed=false").execute();
          result.addAll(files.getItems());          
          request.setPageToken(files.getNextPageToken());
        } 
      catch (IOException e)
      {
        System.out.println("An error occurred: " + e);
        request.setPageToken(null);
      }

 //Print out all the files and folder of root Directory  
  for(File f:result)
  {
      System.out.println("recvd data are: "+f.getTitle());
  }