Properties props = System.getProperties();
Session session = Session.getDefaultInstance(props, null);
session.setDebug(true);
// Get a Store object



Store store = null;
Folder rf = null;
String url="pop3"+"://"+"john"+":"+password+"@"+mailhost.com;

if (url != null) {
URLName urln = new URLName(url);



//it throws no such provider exception here
//it throws no such provider exception here

store = session.getStore(urln);//it throws no such provider exception here
store.connect();
}
String r="INBOX";
rf =store.getFolder(r);

jLabel2.setText(rf.getName());



please write us what can cause this exception ...