The error manifests itself as an ORA-12519 connection refusal error as highlighted by the following partial stack trace:
java.sql.SQLException: Listener refused the connection with the following error: ORA-12519, TNS:no appropriate service handler found The Connection descriptor used by the client was: junit:1521:xe at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112) at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:261) at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:387) at oracle.jdbc.driver.PhysicalConnection.
The suggested fix, and this was written two years ago, is to increase the number of available processes by logging on as SYS and issuing the following command:
ALTER SYSTEM SET PROCESSES=150 SCOPE=SPFILE
…which doesn’t seem like a real fix to me as it just pushes the problem further away.
Yes, I know that Oracle 10g is obsolete and the 11g Express Edition is freely available, but 11g adds yet another layer of unwanted complexity to my requirement for a simple Oracle database.