Does anyone of you have any experience with the other JVMs out there, I’m looking mainly at Avian but it could be any? Are they worth the hassle compared to Sun’s? This could be generally any use although I’m mostly interested in games because that’s what I do right now.
On desktop platforms i’d say they aren’t. On any other platform you might have some issues getting things to run.
Well why are you looking for alternate JVMs? You wont find anything faster than Hotspot 
I’m just generally curious about JVMs and whether the time invested in them is justified by the end product.
The only other one I’ve tried is the Excelsior JET JVM, which is astoundingly fast, but costs money.
Cas 
Woudln’t that cause problems if you want to ship it with a product?
Not at all - you buy a license to use it and deploy its deployables.
Cas
How much faster is it compared to Hotspot? It’s AOT right? I had a brief look at it.
It needs to be about 20% faster, according to MLP fans. I’m going to do some googling and then I’ll come back on the topic of JIT and AOT.
Last time I looked - about 8 years ago now! - it was easily as fast as the Sun server JVM, but with instant startup time like a native application. Awesome.
Cas
It better have improved then otherwise I rather stick with “Oracle” tiered JVM as that’s the client/server hybrid and when JDK8 comes in with Jigsaw. Jigsaw should greatly improve startup as you no longer have to load so many classes - that’s 1/2 the problem there.
Well, no jigsaw won’t change the number of classes you load. Some of the classes might be slightly smaller depending on what they do, but the number will be the same.
I can confirm that JET is pretty fast. I published a benchmark four years ago where some JVMs were compared: http://www.stefankrause.net/wp/?p=9
For interactive applications I’d recommend to compare GC pause times as well. Last time I checked JET had significantly larger pause times than Oracle’s Hotspot VM.
Jet’s got some pretty nifty GC algorithms in there - it’s had incremental collection for a long time, and escape analysis and stack allocation. Its most impressive aspect though remains its instantaneous application startup time - my games literally would start up in under a second, where it takes, say 10 seconds with the Hotspot JVM in two-tiered mode.
Cas