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Introduction to XEP

XEP is a lightweight Java SDK that provides high-performance Java technology for persisting simple to moderately complex object hierarchies. XEP projects the data in Java objects as persistent events (database objects that store a persistent copy of the data fields) in an InterSystems IRIS™ database. XEP is optimized for applications that must acquire and persist data at the highest possible speed.

InterSystems IRIS provides Java SDKs for easy relational and object database access. This book discusses XEP object access. See Using Java with InterSystems Software for JDBC relational access.

Requirements and Configuration

This section specifies requirements and provides instructions for configuring your environment to use XEP.


  • A 64–bit Java JDK supported by this release of InterSystems IRIS (see “Supported Java Technologies” in the InterSystems Supported Platforms document for this release).

  • InterSystems IRIS.

Computers that run your Java client applications do not require InterSystems IRIS, but they must have a connection to the InterSystems IRIS Server and must be running a supported version of the Java JDK.


  • When installing InterSystems IRIS, select the Development environment:

    • In Windows, select the Setup Type: Development option during installation.

    • In UNIX® and related operating systems, select the 1) Development - Install InterSystems IRIS server and all language bindings option during installation (see “Standard InterSystems IRIS Installation Procedure” in the UNIX® and Linux section of the Installation Guide).

  • If InterSystems IRIS has been installed with security level 2, open the Management Portal and go to System Administration > Security > Services, select %Service_CallIn, and make sure the Service Enabled box is checked.

    If you installed InterSystems IRIS with security level 1 (minimal) it should already be checked.


All XEP applications require JAR files intersystems-jdbc-3.0.0.jar and intersystems-xep-3.0.0.jar (see “The InterSystems Java Class Packages” in Using Java with InterSystems Software for file location and other details). Your CLASSPATH environment variable must include the full paths to these files. Alternately, they can be specified in the Java command line classpath argument.

Additional Configuration for Windows

The default stack size of the Java Virtual Machine on Windows is too small for running XEP applications (running them with the default stack size causes Java to report EXCEPTION_STACK_OVERFLOW). To optimize performance, heap size should also be increased. To temporarily modify the stack size and heap size when running an XEP application, add the following command line arguments:

   -Xms2500m -Xmx2500m
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