Are there any driver available for JOLAP or Olap4j to access existing OLAP services? I think on OLAP services like Oracle, MS SQL, etc.
We want start a OLAP project with Java? With which of the both API should we start?
olap4j is the perfect Java API for this type of project. It is designed to do for OLAP what JDBC does for relational databases. It allows you to write an application against a server-neutral API, and then run that application against various servers without code changes. Also, the API is easy to learn because it uses the same concepts as JDBC.
Using the XMLA olap4j driver (included with the olap4j distro) you can connect to any OLAP database which has an XMLA driver -- and most of them do. It has been tested against Microsoft SQL Server Analysis Services, SAP BW, and Mondrian, and others. It should work against Oracle's XMLA provider [ http://www.oracle.com/us/corporate/press/173668 ] but I have not tried it.
See www.olap4j.org for more information.
Julian Hyde (olap4j project founder)