What JVM can be run under Mac OS 7.5?

Question

I have a request for a contracting gig and one of the requirements in the first draft of the specs says the software (a GUI application for end-users) should run on Win 2000 and Mac OS 7.5. I have no idea why they would want to support such ancient systems, but I guess it leaves me with Java as the only option other than raw C, or doesn't it?

So if it would be Java, are there restrictions on what Java version I can use on those targets?

Also, though it wouldn't be strictly on topic, I'd appreciate comments on strategies for making software run on both targets. Actually, supporing those ancient systems as well as modern ones might even be harder than supporting Mac and Win, right?

As another sideline, I'd also appreciate facts that could be used to talk the client out of this and make him go with OS X and XP. Like "hey, only 2% of all Macs in use today still use OS older than X".

---

Edit: My main purpose here is to be well prepared technically to negotiate what the specs really should be.

Things like that are often the result of some manager thinking "gee, my aunt still uses OS 9 and I bet, there's people even more old-fashioned, so let's just play it safe and write down 7.5". There's no technical judgement whatsoever involved, and that's OK. It's just that, in those cases, you have to explain carefully what tradeoffs there are and if you succeed, it usually gets you much more realistic specs. It's not even unlikely that they'd ditch Mac OS altogether if they have to bet money on it.

With that kind of specs, if you don't actively help the client reshape them, what's going to happen is, you put the number in the offer that would pay for all the crazy stuff and then yet some, and less experienced competitors won't see all the implications and put a lower number in their offer, get the gig and it all ends in tears for everybody. You can go "heh heh, told you so", but don't get the cash, either.

---

Edit: Thanks for still posting facts and advice although I already accepted an answer to my original question. I'll keep upvoting that stuff, and it certainly helps. Also thanks for empathizing with me and trying to save me from signing a bad contract! But don't worry, I'm not actually going to code for Mac OS 7.5 ... ;-) Really, really overseeing all the implications would be well out of my depth anyway.

Answer 1

I'm not definate on this, but I believe Mac OS 7.5 would only run 1 and 1.1 versions of Java.

Answer 2

It's up to 1.1.8 for all Mac OS Classic (not X)

Answer 3

Unless this is a seriously lucrative contract, or you desperately need the money, I'd recommend running away from it as fast as possible. The chances are the client is not only targeting seriously old OS's, but also old hardware. That'll mean you'll have all sorts of problems with performance (for you can bet the entire value of the contract that they want an app with modern features and performance on this ancient kit). It's near guaranteed to end in tears...

Answer 4

The Java Runtime for MacOS 7.x was called Mac OS Runtime for Java (MRJ) and supported at least Java 1.1.8. If my memory servers me right, the Swing implementation was pretty bad - so you would need to use AWT.

At least on the ancient MacOS systems, you will have stability & performance problems. Don't take this contract, this is guaranteed to end in a fiasco.

Answer 5

Unless this is a seriously lucrative contract I would stay away from this one.

I've worked on contracts like this in the past and they are almost always more trouble than they're worth. Whilst I appreciate you are just trying to be prepared, you really need to find out more about why they want to do this - its pretty unusual.

OTOH. If the contract is a big one and they are only talking a couple machines - it might be worth your while to offer to buy and install machines for them!

Coding for an older VM such as 1.1 will force you to code to a lower common denominator and will add considerably to development and testing time - you need to take this into account. The machine will almost certainly be underpowered in terms of memory and cpu.

Win2k will support at least Java 1.4 and possibly 1.5.

Answer 6

One useful stat is that about 85-90% of all Macs run OS X 10.4 or 10.5. Most of the other 10% are running older versions of OS X.