The very first template in palette section "Shape Nodes" is a plain rectangular node which is the most common element in JSP diagrams (action/process). The elements for "Selection" and "Iteration" are just plain rectangles with an icon in the upper right corner - in yEd, these can be created using the plain rectangle with an additional label in the upper right corner. Additionally, the "Predefined Process" template from the "Flowchart" palette section matches JSP's "Procedure" element.
For convenient access to the templates used in JSP, create a user-defined palette section and add the four required elements to said section.