oauth get request token for google shows "The page you requested is invalid. " - servlets

Question

I am trying to send a request to oauth google to get a request token.i passed all the parameters required.here is the code.please help.
The out put of the below code is a token provided by google to access its users private data.but i am getting the result that the page i requested is invalid.where did i go wrong?
should i pass the scope also in the url?
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws IOException {
try {
String oauthConsumerKey = "my key";
String oauthSignatureMethod = "HMAC-SHA1";
String oauthSignature = "my signature";
// Send the request
URL url = new URL("https://www.google.com/accounts/OAuthGetRequestToken"+oauthConsumerKey+
oauthSignatureMethod+oauthSignature);
URLConnection conn = url.openConnection();
conn.setDoOutput(true);
OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());
//write parameters
writer.flush();
// Get the response
StringBuffer answer = new StringBuffer();
BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String line;
while ((line = reader.readLine()) != null) {
System.out.println("\n" +line);
}
writer.close();
reader.close();
//Output the response
} catch (MalformedURLException ex) {
ex.printStackTrace();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}

Answer 1

As specified in the documentation of the OAuthGetRequestToken call, you are missing some required parameters:
oauth_consumer_key (required)
oauth_nonce (required)
oauth_signature_method (required)
oauth_signature (required)
oauth_timestamp (required)
scope (required)
oauth_callback (required)
Your query URL also has to be in a format like:
https://www.google.com/accounts/OAuthGetRequestToken?param1=value1&param2=value2&...
Please note that the Google OAuth 1.0 API is already deprecated and should not be used for new projects:
Important: OAuth 1.0 has been officially deprecated as of April 20, 2012. It will continue to work as per our deprecation policy, but we encourage you to migrate to OAuth 2.0 as soon as possible.
Further the OAuth 2 flows are way more simple, check out the documentation at Google.