In Part 1: The
Challenge, published this time last week, I introduced a "brain
teaser". The brain teaser asks you to figure out how to allow
images and other files to be meaningfully dropped onto a NetBeans
Platform application, i.e., on the drop something useful should
happen with the dropped file: if the file is an image, the image
should open in the IDE; if the file is a PDF document, the PDF
viewer should open externally; if the file is a text file, it
should open as a...