Sun has defined four JDBC driver types. These are: 1.Type 1: JDBC-ODBC Bridge Driver The first type of JDBC dirver is JDBC-ODBC Bridge which provide JDBC access to any ODBC complaint databases through ODBC drivers. Sun's JDBC-ODBC bridge is example of type 1 driver. 2.Type 2: Native -API Partly - Java Driver Type 2 drivers are developed using native code libraries, which were originally designed for accessing the database through C/C++. Here a thin code of Java wrap around the native code and converts JDBC commands to DBMS-specific native calls.
3.Type 3: JDBC-Net Pure Java Driver Type 3 drivers are a three-tier solutions. This type of driver communicates to a middleware component which in turn connects to database and provide database connectivity.
4.Type 4: Native-Protocol Pure Java Driver Type 4 drivers are entirely written in Java that communicate directly with vendor's database through socket connection. Here no translation or middleware layer, are required which improves performance tremendously.