The Oracle JDeveloper BPEL designer includes a series of activities that can be added to a BPEL process through drag-and-drop. One such activity is the BPEL assign activity, which provides a method for data manipulation, and enables you to transfer information between variables (XML or JSON), expressions, endpoints, and other elements.

In Oracle JDeveloper design time, while configuring a REST binding in a BPEL composite, you must configure the input payload before you invoke the endpoint. You can manipulate the payload variables through the BPEL Assign Activity. See Assign Activity.

From Oracle JDeveloper 14.1.2.0.0 and later versions, you can render a JSON variable as a tree in design time and visually map the child elements before invoking an endpoint.