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Yes. It is not very hard create and make work simple interfaces with buttons, popups, drawers, etc. to create a front-end interface for your application, and you can allways interact with your own language through the use of do shell script command and obj-C/cocoa methods.
If you already installed the Developer Tools, you can explore AppleScript Studio examples in your "/Developer/Examples/AppleScript Studio" folder; and pay special attention to the project "Multi-Language", which shows some samples to integrate Java, C, C++ and Objective-C code.