Make my own GUI Builder in Java NetBeans

I want to create a gui builder(like the one in NetBeans) in the following way : I have made a JSplitPane where in left side I have a JTextField where I write the name of a Swing Component and in the right side I want to appear that component. Something like this :

I want to make that using Reflections. This is first time using it, so please be kind with me and explain me how to make it.

Thank you!