Error Log Trace:
internal Exception: weblogic.jdbc.extensions.ConnectionDeadSQLException: weblogic.common.resourcepool.ResourceDeadException:0:weblogic.common.ResourceException: Could not create pool connection. The DBMS driver exception was: IO Error: The Network Adapter could not establish the connection.
The DB Service went down abrublty as This exception is generated when an application request to get a connection fails because the connection selected to be returned to the application from the pool fails the configured tests.
Weblogic tests a connection before it is given to a client.
Oracle DB Service need to be restarted !!