This is a subject that I am often asked about by developers and support teams changing application configuration details: What is the correct format of JDBC connection strings for the thin driver?
Oracle's JDBC Thin driver uses Java sockets to connect directly to Oracle. It provides its own TCP/IP version of Oracle's SQL*Net protocol. Because it is 100% Java, this driver is platform independent and can also run from a Web Browser (applets).
Old syntax, supporting instance (SID) names only::
New syntax, supporting both SID and SERVICE names:
There are also some drivers that support a URL syntax which allow to put Oracle user id and password in URL.
Finally, you can also give a tnsnames.ora entry-like in the string: