Don't think there is such a thing. I reckon your best shot is to try compiling and running the thing in Jave 1.4 and to fix the bugs. There's not likely to be tons I wouldn't have thought, although it depends on how you've written it and how many 1.5 specific features you've used. Regarding garbage collection and whatnot, I don't think there's any difference, it's generally just if you've used any specific Java 1.5 features.
GUIs will look a bit different when running under the 1.4 JRE as it doesn't support as much graphical niceness in XP and such, but there's not much you can do about that.
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"Programming is like sex, one mistake and you have to support it for the rest of your life." - Michael Sinz |