Review Request JDK-8136930 Examine implications for custom launchers, equivalent of java -X options in particular

[Alan Bateman]

On 04/06/2016 12:10, Remi Forax wrote:

> Hi Mandy,
> did you think about using -J for specifying either VM options or module options (the user really don't care) for custom launchers like we use -J to specify VM option to javac ?
>
If "custom launcher" means the JNI innovation API then you won't be 
using -J, instead you'll specify the VM options via the JavaVMInitArgs 
when creating the VM .Then you'll load and invoke the entry point for 
the tool, maybe specifying options to its entry/main method. To date 
then creating the VM has required specifying these options via the 
non-documented/internal properties so this patch addresses this.

On the other hand, if you mean launching javac or other tools, say with 
ProcessBuilder, then -J should just work as it does now. Also as you 
mention javac then it's important to distinguish the options for the 
compilation environment from the options for the underlying runtime 
environment. One could find oneself doing something doing something like 
`javac -J-addmods -Jfoo -addmods bar ...` for example. It gets more fun 
once you the annotation processing environment into the picture.

Just to put more context on this patch. We are cleaning up the command 
line option handling and trying to get things more consistent. It will 
take a number of steps. One of the patches to proceed this one is an 
entry point that javac can use to pick up the runtime options. There is 
also a recent javac change to pick up options from an environment 
variable in a similar (but not identical) way to _JAVA_OPTIONS. Once all 
the pieces are in then I think the command line option story will be 
much better.

-Alan