Configure a default JDBC transaction-isolation

The JDBC connections can be initialized with specified values of the transaction-isolation, catalog, and read-only values. The <connection> directive configures these:

<database jndi-name="jdbc/example">
  <driver>
    ...
  </driver>
  <connection>
    <transaction-isolation>read-committed</transaction-isolation>
    <read-only/>
  </connection>
</database>