On Wed, 18 Nov 2020 04:19:51 GMT, Lin Zang <lz...@openjdk.org> wrote:
>>> And the old jmap -dump can not accept "gz" option, it fails with error >>> message printed, no matter what jvm version it work with. >> >> I just want to clarify what I was referring to. I was not talking about >> trying to use gz with the old jmap command (from the command line). I was >> asking what happens if you use the old jmap command on a newer jvm that does >> support (and I assume expects) the new "compression level" argument to be >> passed, but it won't be. We've had this issue before. See >> [JDK-8219721](https://bugs.openjdk.java.net/browse/JDK-8219721). I haven't >> had a chance to look at the fix for JDK-8219721 to see if it also solves the >> issue with this change, or if something similar also needs to be done with >> this change. > > Hi @plummercj , > > Thanks for your explaination. I get your point. > The issue of JDK-8219721 was fixed by reverting the problematic change. And > the root cause of that issue is there is fixed limitation of number of > arguments that passing to jvm from attacher, I have figured out a way to > avoid touching it when adding new options to jcmd-alike tools, However this > PR doesn't even exceed the argument limitation, so it doesn't have chance to > cause the similar issue. > > BRs, > Lin So I assume then that the `op->arg(2)` reference will return `NULL` when and older `jmap` is used? Is that correct? ------------- PR: https://git.openjdk.java.net/jdk/pull/1251
