java.sql.SQLException encountered when connecting to Oracle database

Question

I get the following error when I try to run my project:

java.sql.SQLException: Io exception: Connection refused(DESCRIPTION=(TMP=)(VSNNUM=169870080)(ERR=12505)(ERROR_STACK=(ERROR=(CODE=12505)(EMFI=4))))

Any ideas?

Answer 1

Connection refused means that the server is not allowing your client to connect. Double check the server settings and make sure your host is allowed to connect, at the very least.

Answer 2

You're getting an ORA-12505 error ("TNS: listener could not resolve SID given in connection description."). This happens when the SID (System ID) of the database you wish to connect to isn't registered with Oracle's listener. If you can find the JDBC connection information, you may find something that matches this pattern:

jdbc:oracle:thin:[user]/[password]@[host]:[port]:[sid]

In this case, Oracle is telling you that [sid] does not exist on the server [host]. You may be connecting to the wrong server.