This question is already addressed in several FAQs if you search for applet and JDBC.

As already mentioned, untrusted applets can only communicate from the server from which it came. Thus, the web server must serve double duty as the database server, too.

sure, it is possible. make sure your driver is loaded into the JVM of where applet is loaded (which means you will need to jar the applet), import the class, load the driver, get the connection, execute a statement and get the resultset to display. if you have an application server that is managing your connections through the connection pool, you will need to do JNDI lookup for the datasource in order to obtain a connection. if this is the case in your design, you will need your app server client jar in the applet's JVM. most app server provide this jar file in the installation.