When i am trying to connect to one of our databases, i am getting an error that
IO Error: The Network adapter could not establish the connection
Vendor code 17002
Tns No Listener issue.
Request you to check and let me know the steps to go ahead on the issue.
What application is returning that error? Oracle doesn't return error messages in that format, and if you took "Vendor code 17002" to be the apps capturing and repackaging of oracle's error code, there is no ora-17002 related to 'no listener'.
Let's start by seeing your tnsnames.ora file on the client machine. The the output of 'tnsping <mydb>' on the client machine, where <mydb> is the name of the relevent entry in your tnsnames.ora file. Also the output of 'lsnrctl status' and the contents of the listener.ora file on the database host machine.
An Oracle "no listener' message (ORA-12541) means that when the client request reached the specified host machine, there was no oracle listener on the specified port.
Also confirm you have a database. SQL Developer is just a client.
I talk about this a bit here: http://searchoracle.techtarget.com/tip/Battle-through-the-recurring-Oracle-TNS-mistakes-admins-make
Basically, there is no listener running on that host with that port. Make sure you have the host and port defined correctly. Then go to that server and make sure the listener is actually running and using that port.