which driver converts jdbc calls directly into the vendor-specific database protocol
JDBC driver The JDBC type 3 driver, also known as the Pure Java driver for database middleware,[7] is a database driver implementation which makes use of a middle tier between the calling program and the database. The middle-tier (application server) converts JDBC calls directly or indirectly into a vendor-specific database protocol.
Java virtual machine A Java virtual machine (JVM) is a virtual machine that enables a computer to run Java programs as well as programs written in other languages and compiled to Java bytecode. The JVM is detailed by a specification that formally describes what is required of a JVM implementation. Having a specification ensures interoperability of Java programs across different implementations so that program authors using the Java Development Kit (JDK) need not worry about idiosyncrasies of the underlying hardware platform.