Create a more abstract way for showing popups / dialog boxes

Some times you need the possibility provide some kind of dialog to ask a user for an input. In my current case, i am implementing a way to pay via online banking. I have a list of 100 transaction numbers (tan). After initiating a payment via onlinebanking, the bank asked for e. g. tan number 12. Now we need a way to show a little dialog in which the user can enter the tan.

Each client - swing and webu - have their own way to show a dialog/popup window. This means, if i want to show a popup from e. g. within a SvrProcess, i would need to determine the client and decide by myself how to show the dialog. I would like to have an more abstract way to show it. There should be an all present dialog class which decides by itself if to show the dialog (wheather it is swing or webui) or to do nothing, e. g. if it was called by a server process which has no gui.