Got minus one from a read call oracel code example

Example: get minus one from a read call

I got the same issue but following steps worked for me, it seems Gaurav also has shared it already:

1.Go to the folder where you have installed the database (Like: F:\app)
2.Here you will be able to see many folders, go to product\11.2.0("your databse version")\dbhome_1\NETWORK\ADMIN
3.find listener.ora file and open as text file
4.Check for the port number in that file
5.Now provide that port number while doing connection in sql developer.