how to create web service datasource for Google cloud APIs

We need to create a web service data source to access google apis.

I followed the steps mentioned in the below document 

http://teiid.github.io/teiid-documents/master/content/admin/OAuth_Authentication_With_REST_Based_Services.html

But getting below error after entering the  Access Token URL.
Could you please provide solution on it.

Error logs.

===========

WARNING: Default key managers cannot be initialized: Password must not be null
java.security.UnrecoverableKeyException: Password must not be null
at sun.security.provider.JavaKeyStore.engineGetKey(JavaKeyStore.java:124)
at sun.security.provider.JavaKeyStore$JKS.engineGetKey(JavaKeyStore.java:55)
at java.security.KeyStore.getKey(KeyStore.java:1011)
at sun.security.ssl.SunX509KeyManagerImpl.<init>(SunX509KeyManagerImpl.java:133)
at sun.security.ssl.KeyManagerFactoryImpl$SunX509.engineInit(KeyManagerFactoryImpl.java:70)
at javax.net.ssl.KeyManagerFactory.init(KeyManagerFactory.java:256)
at org.apache.cxf.configuration.jsse.SSLUtils.loadDefaultKeyManagers(SSLUtils.java:116)
at org.apache.cxf.configuration.jsse.SSLUtils.getDefaultKeyStoreManagers(SSLUtils.java:89)
at org.apache.cxf.transport.https.SSLUtils.getSSLContext(SSLUtils.java:75)
at org.apache.cxf.transport.https.HttpsURLConnectionFactory.decorateWithTLS(HttpsURLConnectionFactory.java:144)
at org.apache.cxf.transport.https.HttpsURLConnectionFactory.createConnection(HttpsURLConnectionFactory.java:101)
at org.apache.cxf.transport.http.URLConnectionHTTPConduit.createConnection(URLConnectionHTTPConduit.java:121)
at org.apache.cxf.transport.http.URLConnectionHTTPConduit.setupConnection(URLConnectionHTTPConduit.java:125)
at org.apache.cxf.transport.http.asyncclient.AsyncHTTPConduit.setupConnection(AsyncHTTPConduit.java:190)
at org.apache.cxf.transport.http.HTTPConduit.prepare(HTTPConduit.java:505)
at org.apache.cxf.interceptor.MessageSenderInterceptor.handleMessage(MessageSenderInterceptor.java:47)
at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:308)
at org.apache.cxf.jaxrs.client.AbstractClient.doRunInterceptorChain(AbstractClient.java:701)
at org.apache.cxf.jaxrs.client.WebClient.doChainedInvocation(WebClient.java:1086)
at org.apache.cxf.jaxrs.client.WebClient.doInvoke(WebClient.java:932)
at org.apache.cxf.jaxrs.client.WebClient.doInvoke(WebClient.java:901)
at org.apache.cxf.jaxrs.client.WebClient.form(WebClient.java:434)
at org.apache.cxf.rs.security.oauth2.client.OAuthClientUtils.getAccessToken(OAuthClientUtils.java:301)
at org.apache.cxf.rs.security.oauth2.client.OAuthClientUtils.getAccessToken(OAuthClientUtils.java:225)
at org.teiid.oauth.OAuthUtil.oauth20Flow(OAuthUtil.java:158)
at org.teiid.oauth.OAuthUtil.main(OAuthUtil.java:76)
at org.jboss.modules.Module.run(Module.java:352)
at org.jboss.modules.Module.run(Module.java:320)
at org.jboss.modules.Main.main(Main.java:593)

Exception in thread "main" org.apache.cxf.rs.security.oauth2.provider.OAuthServiceException: server_error
at org.apache.cxf.rs.security.oauth2.client.OAuthClientUtils.getAccessToken(OAuthClientUtils.java:323)
at org.apache.cxf.rs.security.oauth2.client.OAuthClientUtils.getAccessToken(OAuthClientUtils.java:225)
at org.teiid.oauth.OAuthUtil.oauth20Flow(OAuthUtil.java:158)
at org.teiid.oauth.OAuthUtil.main(OAuthUtil.java:76)
at org.jboss.modules.Module.run(Module.java:352)
at org.jboss.modules.Module.run(Module.java:320)
at org.jboss.modules.Main.main(Main.java:593)
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