Java: Require library to generate histological cut

I like to generate images like the following:

The generated images dont have to be as good as the images above. Important is the background (something like in the first image is ok) and the cell nucleus (the dark points).

Unfortunately i did not find a library which has good support to generate such things. Maybe someone knows a java library which could help to generate such images?

Thank you very much

Best regards

Kevin