oAuthService=LinkedInOAuthServiceFactory.getInstance().createLinkedInOAuthService(key, secret); request=oAuthService.getOAuthRequestToken("http://www.google.com"); Exception in thread "main" com.google.code.linkedinapi.client.oauth.LinkedInOAuthServiceException: oauth.signpost.exception.OAuthCommunicationException: Communication with the service provider failed: Server returned HTTP response code: 400 for URL: https://api.linkedin.com/uas/oauth/requestToken at com.google.code.linkedinapi.client.oauth.LinkedInOAuthServiceImpl.getOAuthRequestToken(LinkedInOAuthServiceImpl.java:180) at com.cpt.linkedin.linkedINExample.authorize(linkedINExample.java:57) at com.cpt.linkedin.linkedINExample.main(linkedINExample.java:38) Caused by: oauth.signpost.exception.OAuthCommunicationException: Communication with the service provider failed: Server returned HTTP response code: 400 for URL: https://api.linkedin.com/uas/oauth/requestToken at oauth.signpost.AbstractOAuthProvider.retrieveToken(AbstractOAuthProvider.java:214) at oauth.signpost.AbstractOAuthProvider.retrieveRequestToken(AbstractOAuthProvider.java:69) at com.google.code.linkedinapi.client.oauth.LinkedInOAuthServiceImpl.getOAuthRequestToken(LinkedInOAuthServiceImpl.java:172) ... 2 more Caused by: java.io.IOException: Server returned HTTP response code: 400 for URL: https://api.linkedin.com/uas/oauth/requestToken at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:532) at sun.net.www.protocol.http.HttpURLConnection$6.run(HttpURLConnection.java:1458) at java.security.AccessController.doPrivileged(Native Method) at sun.net.www.protocol.http.HttpURLConnection.getChainedException(HttpURLConnection.java:1452) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1106) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:254) at oauth.signpost.basic.HttpURLConnectionResponseAdapter.getContent(HttpURLConnectionResponseAdapter.java:18) at oauth.signpost.AbstractOAuthProvider.handleUnexpectedResponse(AbstractOAuthProvider.java:228) at oauth.signpost.AbstractOAuthProvider.retrieveToken(AbstractOAuthProvider.java:189) ... 4 more Caused by: java.io.IOException: Server returned HTTP response code: 400 for URL: https://api.linkedin.com/uas/oauth/requestToken at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1403) at java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:397) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:338) at oauth.signpost.basic.HttpURLConnectionResponseAdapter.getStatusCode(HttpURLConnectionResponseAdapter.java:22) at oauth.signpost.AbstractOAuthProvider.retrieveToken(AbstractOAuthProvider.java:178) ... 4 more