Is there a way to include a VM parameter inside a .jar?

Question

I have a game implemented in Java that was having a problem when running too much code from scripts: depending on the script language, the game could have these "hiccups" where the game would freeze for a couple frames every now and then, making the game "jerky" at times.

After some research, I discovered that was happening when the Garbage Collector decided to run. After some more research and testing, I discovered that using the incremental garbage collector (by using the -Xincgc VM parameter) fixed the problem. Yes, I am aware it makes the GC run about 10% slower, but it is the cost I pay.

With that background information, now what I want to do is package the game in a .jar like I have been doing so far, but I know no way of making the application use the incremental GC without using -Xincgc, and I didn't want to create .bat/.sh files where before the user only had to double-click the .jar.

Is there any way to make the .jar run with the incremental GC without needing some kind of loader (.bat/.sh) or wrapper around it? Is there some way to include that parameter in the .jar?

Answer 1

No, there's no way to do that. VM arguments can only be supplied as command-line parameters to JVM invocation: Java Tool

Answer 2

I don't know of too many java apps outside of internal coorporate or dev stuff that people run via clicking a jar. Even a shortcut can specify this. Fancier options exist that let you create an exe, run as a service, or even wrap the whole thing in an installer... if we are talking windows, similar things exist for linux.

Answer 3

You can definitely do this with JNLP, which can be configured to add a shortcut to the desktop and automatically keep jars up to date, among other things.

Answer 4

Besides Java Web Start, you could consider wrapping with JSMooth. It gives an EXE which in turn invokes the JVM - you can provide arguments there.

Answer 5

From just a jar file, you can't do this. Adding Java WebStart can allow you to add java VM commands. If you are not against wrapping the jar in an executable Launch4J will wrap the jar in a executable as well. It only makes a windows exe, but it can make it on linux or windows. I haven't found a good alternative for linux.

Answer 6

One option - I always wondered - is to re-run the jar program with Runtime.exec() call when the parameters are inadequate? Never tried it but seems possible.