June 11, 2015 11:59:59

The following error occurred while MyEclipse DB Explorer was configuring the Oracle 10g Link database:

Connection refused (description= (tmp=) (vsnnum=153093120) (err=12505) (error_stack= (error=) (code=12505)))

You can connect to the database directly via Plsql, or you can connect to the database via Sqlplus

After finding the relevant data, the cause of the problem is as follows:
When JDBC connects to an Oracle database, it needs to use the database's Sid_name (that is, the Oracle instance name), not the database's Services_name
When you use Plsql to connect to a database, you only need the services_name of the database, so modify services_name in the connection string to Sid_name

You can view the SID of the current database in a few ways:

Select instance_name from V$instance;

Instance_name
----------------
Myorcl

June 11, 2015 11:59:59