Control node type can be initial node, final node, fork node, join node, decision node, and merge node.
Initial
An initial node is a control node at which flow starts when the activity is invoked.
An activity may have more than one initial node.
Final
An activity final node stops all flows in an activity. A flow final destroys all tokens that arrive at it. It has no effect on other flows in the activity.
Decision
A decision node is a control node that chooses only one flow between several outgoing flows. Outgoing flows are selected by evaluating their guards.
Merge
A merge node brings together multiple alternate flows. It is not used to synchronize concurrent flows but to accept one among several alternate flows.
Fork
A fork node splits a flow into multiple concurrent flows. A fork node has one incoming edge and multiple outgoing edges
Junction
A join node synchronizes multiple flows A join node has multiple incoming edges and one outgoing edge.