I get this error message when tried to test db connection via a data source from WAS admin console:
The test connection operation failed for data source Trade on server nodeagent at node Node02 with the following exception: java.sql.SQLException: [jcc][t4][3.57.82] Null userid is not supported. ERRORCODE=-4461, SQLSTATE=42815DSRA0010E: SQL State = 42815, Error Code = -4,461. View JVM logs for further details.
This error can be resolved by restarting dmgr, nodeagents and app server processes.