What is the difference between OCI and THIN driver connection with data source connection between java and oracle XE?

Oracle provides four types of drivers for their database, but I'll only enumerate the two you asked about.

The OCI driver is a type 2 JDBC driver and uses native code to connect to the database. Thus, it is only an option on platforms that have native Oracle drivers available and it is not a "pure" Java implementation.

Oracle's JDBC Thin driver is a type 4 JDBC Driver that uses Java sockets to connect directly to Oracle. It implements Oracle's SQL*Net TCP/IP protocol directly. Because it is 100% Java, it is platform independent and can also run from an Applet. (not that you should)

Both the JDBC thin driver and the JDBC OCI driver speak the same network protocol. From the server standpoint there is no difference between the two. The JDBC thin driver is 100% Java and comes in a single standalone jar (some extra jars will be needed for advanced features). The JDBC OCI driver makes JNI calls to the OCI C client library and hence depends on the Oracle full client to be installed (OCI is also what sqlplus uses). Oracle recommends to use the JDBC thin driver which is what most customers use. It's the fastest driver and the most robust one.