As the power and complexity of Java applications increase to serve expanding business needs, so does the need for the reliable availability — the “persistence” — of the data in your data stores. This article introduces you to the SAP Web Application Server 6.40 implementation of the Java Data Objects (JDO) standard, a simple interface that enables you to persist data for any Java application, without having to change your application source code, and without having to know any language other than Java. It shows you how to create persistent objects using JDO, and walks you through some real-world coding examples that demonstrate how you can use JDO effectively in your own business applications.