This illustration depicts an MDB interacting with an Oracle JMS destination. In the upper-left corner, there is a box labeled "OC4J". Within this box is a circle labeled "MDB". In the upper right, there is a cylinder representing a database, and within this cylinder is a rectangle labeled "Queue or Topic". There is a straight line from the "MDB" circle inside the "OC4J" box to the "Queue or Topic" rectangle inside the cylinder. This line is labeled "JMS connection over a JDBC connection". Beneath the "OC4J" box is a circle labeled "CLIENT", with an arrow going from this circle to the "Queue or Topic" rectangle in the cylinder.