What is your version of SQL Developer?
Post a screenshot of your connect dialog.
Are you trying to connect to a database you have installed yourself?
You are aware that SQL Developer does not come with a bundled database.
Can someone please help me connect oracle sql developer?
When I try to create a table (connection) I receive the failure: IO Error
The network Adapter could not establish the connection.
Please and thank you
A table is an object within a database. A "connection" is something different entirely. So your statement equating a table with a connection ("When I try to create a table (connection)" is very confusing.
As cormaco said, SQL Dev is just a GUI client. It does not come with a database. Show us a screenshot of your connection definition with SQL Dev.
I'm going to guess you don't actually have an oracle database to connect to - here's some options for getting started quickly.
Well, assuming the database is installed, here are some other things to check:
1) All the following need to be correct:
SID (actually the Service name is preferred)
2) If all is well with (1), and connect still fails with that message, then either your listener is not running, or the database is not registered to it.
3) So first check the listener's status from a Cmd Window, probably launched with "Run as adminstrator" in case other actions are required.
Either the listener is not running, or it is running but the "xe" Service is not shown as registered. A working 11g configuration will show something like:
4) But if the listener is not running, execute: lsnrctl start
5) If another check of listener status still does not show an "xe" Service, then make sure the database is started. Probably from the Oracle 11g option on your Start menu, or
execute: net start OracleServiceXE
Hope this helps