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You might be thinking of JOptionPane and its show dialog methods. You would normally learn that before learning about JDialog, but I could be wrong.

Nope, not difficult. It is amazing and especially challenging to those new to OOP who have not yet switched their thinking of programming as creating and acting on objects.

For Java information...

I suggest you use a JDialog as the second container rather than another JFrame. And, yes, of course it's possible. If you have code that tries to accomplish this amazing feat but falls short, then...