Resolution:
Support for connecting to a failover cluster is available in DataDirect Connect for JDBC driver Version 3.4 and above.

A new option called 'AlternateServers', allows a list of additional database servers to be specified. The format is as follows :

AlternateServers= (servername1:port1,servername2:port2, ..., servernameN:portN)

To use the AlternateServers connection option, you must specify the primary ServerName and PortNumber values in the URL or DataSource

Here is an example URL to connect to an Oracle 9i RAC :

jdbc:tibcosoftwareinc:oracle://server1:1521;SID=TEST;AlternateServers=(server2:1521,server3:1521,server4:1521)

Specifying the above URL causes the driver to attempt to connect to the TEST database on server1 using port 1521. If that connection attempt  fails, the driver tries to connect to the TEST database on server2. If that attempt fails, the driver attempts to connect to  server3, and so on, until all servers in the list are tried

PLease refer the following link for more details
http://www.datadirect.com/developer/jdbc/jdbc_with_rac/index.ssp

Keywords : Oracle, RAC, Real Application Cluster, JDBC