OOZIE-2748 introduced a change which eliminates null arguments in certain actions. For example if the argument list in a Java action contains <arg></arg> then Oozie used to pass null in the args array to the main() method.
OOZIE-2748, null elements are removed. However, there are Oozie users who actually rely on this behaviour and now their workflows are broken.
We should add a property which tells Oozie whether nulls should be inserted or not.