I got the following error when accessing an ADF application page which utilizes a datasource connection created on Weblogic Server for displaying some data. Maximum pool size is 150 and the application is accessed rarely by different people.
(Increased the pool size to ensure connection pool does not exhaust now and then)
Have you checked the server's jndi tree and observed the JNDI reference "jdbc.EBillingDS" is available there? In case its not the case then the application look-up is going to fail every time. But what you can also check is that whether the data source you are configuring is even running or not. Best way to check/confirm it would be restarting the server or monitoring the connection pool for the DS.
Well, now that it's working, the only thing that the save button could have done was to
finish/commit the deployment of that DataSource, and/or changing the jndi name...
Some crucial aspect of the DataSource definition/deployment had not actually been
committed yet, and your hitting the save button completed it.