First Open Java API for OLAP Available

Open source business intelligence (BI) vendor Pentaho Corporation today released version 1.0 of olap4j, an open Java API for building OLAP applications.

According to the originator of olap4j, Julian Hyde, olap4j is a programming model similar to JDBC, the Java API that defines how a client accesses a database. It shares some of its core classes and has many of the same advantages. Hyde describes it on the olap4j Web site his way: "olap4j is to multidimensional data what JDBC is for relational data." The olpa4j API allows you to write an OLAP app in Java for one server and easily switch it to another.

Online Analytical Process (OLAP), the database technology for dealing with high performance querying and reporting, organizes data hierarchically and stores it in multidimensional "cubes" instead of flat tables.

Proprietary OLAP APIs are designed to work with specific OLAP servers, but the olap4j API is designed to work on any backend OLAP server.

"Because olap4j is an extension to JDBC," Hyde explains on his blog "any developer who has accessed databases from Java can easily pick it up. And it can leverage standard JDBC services such as connection pools and driver managers."

Hyde is chief architect at Pentaho and founder of the Mondrian open-source OLAP engine. He started the olap4j project in 2006. This release, he says, "is a big deal for an open source project."

"olap4j was created to address the lack of an open standard API for Java access to OLAP servers," Hyde wrote. "Microsoft had created APIs for the Windows platform (OLE DB for OLAP, and later ADOMD.NET) and for Web services (XML for Analysis) and in due course other vendors adopted those APIs as standards, but on Java, the main platform for enterprise applications, you were always tied to the API provided by your OLAP server vendor."

olap4j 1.0 is an extension of the JDBC 4.0 specification, which means that Java jocks who've done any database programming will find it familiar. It leverages such Java services as connection pools, driver management and directory services.

Hyde conceived of the project as a collaboration among vendors and individual contributors in the open source and BI communities. Pentaho now heads a growing list of organizations contributing to the olap4j API, including the SQL Power Group, Jedox, Matrix CPM Solutions, Saiku and Aschauer EDV GMBH.

"People are using olap4j in ways that I couldn't imagine when I started the project four years ago," he wrote. "That's the exciting thing about an open source project becomes successful and starts to gain momentum: you can expect the unexpected."

olap4j 1.0 is available for download now at

About the Author

John K. Waters is the editor in chief of a number of sites, with a focus on high-end development, AI and future tech. He's been writing about cutting-edge technologies and culture of Silicon Valley for more than two decades, and he's written more than a dozen books. He also co-scripted the documentary film Silicon Valley: A 100 Year Renaissance, which aired on PBS.  He can be reached at [email protected].