Megathin versus opljdbc drivers 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.