Type 1 –(JDBC-ODBC bridge, plus an ODBC driver). The JDBC
API are implemented as mapping to other Database driver API.
All the JDBC calls will be translated to an ODBC request and
sent to ODBC driver,which then will be take care of the
request. This translation results in the degradation of
performance

Type4 -are direct-to-database pure Java drivers ("thin"
drivers). A Type 4 driver takes JDBC calls and translates
them into the network protocol (proprietary protocol) used
directly by the DBMS. Thus, client machines or application
servers can make direct calls to the DBMS server.Each DBMS
requires its own Type 4 driver; therefore, there are more
drivers to manage in a heterogeneous computing environment,
but this is outweighed by the fact that Type 4 drivers
provide faster performance and direct access to DBMS features.