Edit or add flow variables using java code. The node is analogous to the Java Snippet node: In the central panel, added java code to add or modify variables. The variables available at the input are listed on the left.
It is also possible to use external java libraries (that is, libraries that are not part of java boot classpath). In order to include such external jar or zip files, add their location in the "Additional Libraries" tab using the control buttons.
You can define reusable templates with the "Create templates..." button. Templates are stored in the users workspace by default and can be accessed via the "Templates" tab.