The "admin" commands can throw heap errors, especially during add-in installations, when there is no enough memory for them to work on, and when dealing with large data sets. A sample of the error that can be throw is provided below:
1/5/18 8:17 AM (admin) at com.niku.union.xml.dom.DOMWalker.traverseIntern(DOMWalker.java:92)
1/5/18 8:17 AM (admin) at com.niku.union.xml.dom.DOMWalker.traverse(DOMWalker.java:36)
1/5/18 8:17 AM (admin) ERROR 2018-01-05 08:17:31,952 [main] union.service rollback exception
1/5/18 8:17 AM (admin) java.lang.OutOfMemoryError: Java heap space
1/5/18 8:17 AM (admin) at java.util.ArrayList.toArray(ArrayList.java:407)
Look for these errors in either the terminal or the admin.log.