Other error messages

In addition to error messages that DITA Open Toolkit generates, you might also encounter error messages generated by Java or other tools.

Out of Memory error

In some cases, you might receive a message stating the build has failed due to an Out of Memory error. Try the following approaches to resolve the problem:

  1. Increase the memory available to Java.
  2. Reduce memory consumption by setting the generate-debug-attributes option to false. This option is set in the lib/configuration.properties file. This will disable debug attribute generation (used to trace DITA-OT error messages back to source files) and will reduce memory consumption.
  3. Set dita.preprocess.reloadstylesheet Ant property to true. This will allow the XSLT processor to release memory when converting multiple files.
  4. Run the transformation again.


If you receive a java.lang.UnsupportedClassVersionError error message with an Unsupported major.minor version and a list of Java classes, make sure your system meets the minimum Java requirements as listed in the Release Notes and installation instructions.

Unable to locate tools.jar

If a Java Runtime Environment (JRE) is used when building output via Ant, the Unable to locate tools.jar error may appear. This message is safe to ignore, since DITA-OT does not rely on any of the functions in this library. If a Java Development Kit (JDK) is also installed, setting the JAVA_HOME environment variable to the location of the JDK will prevent this message from appearing.