'Java heap space' error on prod build

[lesley.oakey]

The dev builds work absolutely fine, but trying to build for production (eg build-desktop-production) on the default generated project results in java heap space errors.

..\my-app\node_modules\@sencha\cmd\dist\plugin.xml:333: The following error occurred while executing this line:
..\my-app\node_modules\@sencha\cmd\dist\ant\build\app\build-impl.xml:274: The following error occurred while executing this line:
..\my-app\node_modules\@sencha\cmd\dist\ant\build\app\js-impl.xml:186: com.sencha.exceptions.BasicException: Java heap space

Has anyone else had this issue or know how to fix it?

[lesley.oakey]

Sigh, never mind. The answer was here on these very forums: https://www.sencha.com/forum/showthread.php?343463-Failed-to-start-reactor-kitchensink-Java-heap-space-error

I'd tried setting _JAVA_OPTIONS before but hadn't been rebooting my machine so it hadn't been fixed.