execute events read from JSON

I am reading two things from a JSON file:

actionOnPress:"robot.KeyPress(e)"

(robot being a java.awt.robot instance) and

event:"KeyEvent.VK_4"

I want to execute

robot.KeyPress(KeyEvent.VK_4)

what is the easiest way (best without needing to download libraries) to execute this? This code is supposed to also work with robot.mousePress and robot.mouseMove etc.

I already tried different things with ScriptEngine, but none of it seems to work.

Thank you very much, Kamik423

EDIT: should be universal. The user should be able to specify different events like FOR EXAMPLE robot