AWI allows users to save a workflow without adding any lines for predecessors / successors between objects. In the Java UI, the user is alerted that they have an object that has no predecessors / successors and asked if they are sure they want to save it.
This behavior is by design. When no lines are drawn to connect objects in a workflow, the AE executes all objects contained within the workflow simultaneously. No warning is issued when saving / executing the workflow (as it is in the Java UI) and execution occurs as normal.