I am following the steps and i have got the consumer key and pre request code , using these a call is made to get_token
eg:
String url2 = "https://api.login.yahoo.com/oauth/v2/get_token?"+ "&oauth_consumer_key=dj0yJmk9WnhsVVZvSDhkYTVpJmQ9WVdrOWMwRlVZV0p2TkRnbWNHbzlNV
FE0TURJek5qVTJNZy0tJnM9Y29uc3VtZXJzZWNyZXQmeD0yNg--"+
"&oauth_signature_method=PLAINTEXT"+
"&oauth_nonce="+(System.currentTimeMillis()/1000)+Math.random()*100+
"&oauth_timestamp="+(System.currentTimeMillis()/1000)+""+
"&oauth_signature=cd749fd91ef7380e9bebd581a33e708e0d4d42f4"+
// "&oauth_verifier=Boasvd78"+
"&oauth_version=1.0"+
"&oauth_token="+requestToken;

Is there something wrong in this , i am always get an 401 error