When you pass empty String as a parameter to org.modeshape.jcr.JcrNodeTypeTemplate.setPrimaryItemName(String) or org.modeshape.jcr.JcrNodeDefinitionTemplate.setDefaultPrimaryTypeName(String) method (perhaps also other methods in templates), it causes IllegalArgumentException.

It'd be better, if these methods just just log some warning and do nothing with empty String argument (or even null). If it is not against the specification, of course.