cvc-elt.1: Cannot find the declaration of element 'oauth-config'. [2]

Question

I have started implementing Joauth authentication. Ofcourse, right now i am doing copy paste to learn how it works.

currently i am facing issue "cvc-elt.1: Cannot find the declaration of element 'oauth-config'. [2]"

I have taken reference URL and that URL is beneath.

• JOAuth, a java-based OAuth 1 (final) and OAuth 2 (draft 10) library. How do I use it?

oauth-config.xml code snippet

<?xml version="1.0" encoding="UTF-8" ?>
<oauth-config>
 <!-- Twitter OAuth Config -->
 <oauth name="twitter" version="1">
  <consumer key="TWITTER_KEY" secret="TWITTER_SECRET" />
  <provider requestTokenUrl="https://api.twitter.com/oauth/request_token" authorizationUrl="https://api.twitter.com/oauth/authorize" accessTokenUrl="https://api.twitter.com/oauth/access_token" />
 </oauth>

 <!-- Facebook OAuth -->
 <oauth name="facebook" version="2">
  <consumer key="APP_ID" secret="APP_SECRET" />
  <provider authorizationUrl="https://graph.facebook.com/oauth/authorize" accessTokenUrl="https://graph.facebook.com/oauth/access_token" />
 </oauth>

 <service path="/request_token_ready" class="com.neurologic.music4point0.oauth.TwitterOAuthService" oauth="twitter">
  <success path="/start.htm" />
 </service>

 <service path="/oauth_redirect" class="com.neurologic.music4point0.oauth.FacebookOAuthService" oauth="facebook">
  <success path="/start.htm" />
 </service>
</oauth-config>

can u help what is the wrong here? i think we need to add "dtd" file. can u please suggest me here. If you need any additional info, please suggest me.

Really appreciable, Pradeep