native-image --no-server -J-Xmx has no effect

[jroper]

Using native-image --no-effect -J-Xmx2048m ... has no effect, in spite of the documentation saying it's supported, because the custom -Xmx is appended to the arguments after native-image's own calculated -Xmx, and the JVM is taking the first -Xmx it finds.

This was also reported in a comment on #903, but that issue was closed.

By the way, why does it default to using 80% of the machines physical memory? On my machine, I'm running browsers and slack and all sorts of other stuff, I definitely never have 80% of my physical memory free to do just one thing, so I frequently see my native-image processes being OOM killed by the OS due to this. I don't understand why that default would be chosen, it only makes sense on a dedicated build machine, and even then, build tools (like Maven) that are likely invoking the graal compiler are probably already taking up more than 20% of the available memory.

[olpaw]

Using native-image --no-effect -J-Xmx2048m ... has no effect

If you are using server-based building -J-Xmx2048m indeed has no effect. This is for a reason. In server mode native-image decides the mem args so that it can reuse already running servers as much as possible.

To ensure -J-Xmx2048m gets taken into account you have to combine it with --no-server.