OpenLink's megathin JDBC drivers adhere to the "Pure JAVA" standard designated by Sun.
Megathin drivers contain no references to external .dll's, and they do not make non-JAVA specific system calls.
As a result, megathin drivers can only establish Type 3 JDBC connections.
OpenLink's opljdbc drivers make reference to external .dll's.
These .dll's allow the opljdbc drivers to establish Type 1, 2, and 3 JDBC connections.