In an enterprise environment, the Role and Resource Service driver will require more maximum Java heap than the default amount defined in IDM. A maximum Java heap size of 256mb is suggested in order to avoid OutOfMemoryError conditions.
The Java heap size can be specified via iManager under the Misc section of the Driver Set properties or by setting the DHOST_JVM_INITIAL_HEAP and DHOST_JVM_MAX_HEAP environment variables. See the Identity Manager Common Driver Administration Guide for more information on configuring Java VM options.