# 7.9.x with OpenJDK9 Garbage Collection

**URL:** <https://forum.inductiveautomation.com/t/7-9-x-with-openjdk9-garbage-collection/17992>\
**Category:** Ignition\
**Created:** [May 10, 2018, 8:49pm UTC](https://forum.inductiveautomation.com/t/7-9-x-with-openjdk9-garbage-collection/17992 "2018-05-10T20:49:04Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![JordanCClark](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jordancclark/32/83362_2.png) [@JordanCClark](https://forum.inductiveautomation.com/u/JordanCClark)\
**Post date:** [May 10, 2018, 8:49pm UTC](https://forum.inductiveautomation.com/t/7-9-x-with-openjdk9-garbage-collection/17992/1 "2018-05-10T20:49:04Z")

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I spun up a new VM today with OpenJDK9 (Zulu) and Ignition 7.9.7. Poking around the ignition.conf file, I noticed the line commented out abut using Concurrent Mark and Sweep GC. It gives me two questions:

1. Does this mean that G1GC is used by default? Java 9 and all.

2. If I restore a gateway backup to this, will this get overwritten with old settings?

Not that I’m opposed to playing around, but this may get upgraded for use as my production server, and I’m feeling lazy. 😉

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**Author:** ![AIO](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/aio/32/87549_2.png) [@AIO](https://forum.inductiveautomation.com/u/AIO)\
**Post date:** [May 10, 2018, 9:32pm UTC](https://forum.inductiveautomation.com/t/7-9-x-with-openjdk9-garbage-collection/17992/2 "2018-05-10T21:32:11Z")

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I’d expect it to get overwritten - our recent gateway restores wrote settings over the defaults. (including G1GC and ram configuration that we use).

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**Author:** ![KathyApplebaum](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kathyapplebaum/32/7261_2.png) [@KathyApplebaum](https://forum.inductiveautomation.com/u/KathyApplebaum)\
**Post date:** [May 10, 2018, 10:58pm UTC](https://forum.inductiveautomation.com/t/7-9-x-with-openjdk9-garbage-collection/17992/3 "2018-05-10T22:58:35Z")

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Yes, it’s using the default, which for Java 9 is G1GC, unless you’ve set something different.

In 7.9.8 we’re making G1GC the default for Java 8, too (unless you change the .conf file) because we didn’t realize how awful parallel GC is. 😳

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [May 11, 2018, 1:26am UTC](https://forum.inductiveautomation.com/t/7-9-x-with-openjdk9-garbage-collection/17992/4 "2018-05-11T01:26:44Z")

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> [@KathyApplebaum](#):
>
> In 7.9.8 we're making G1GC the default for Java 8, too

It's about [expletive] time!

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**Author:** ![JordanCClark](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jordancclark/32/83362_2.png) [@JordanCClark](https://forum.inductiveautomation.com/u/JordanCClark)\
**Post date:** [May 11, 2018, 1:34pm UTC](https://forum.inductiveautomation.com/t/7-9-x-with-openjdk9-garbage-collection/17992/5 "2018-05-11T13:34:43Z")

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@AIO, I had figured, but thanks for the sanity check. 🙂

@KathyApplebaum, I appreciate the info!

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**Author:** ![KathyApplebaum](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kathyapplebaum/32/7261_2.png) [@KathyApplebaum](https://forum.inductiveautomation.com/u/KathyApplebaum)\
**Post date:** [May 11, 2018, 2:21pm UTC](https://forum.inductiveautomation.com/t/7-9-x-with-openjdk9-garbage-collection/17992/6 "2018-05-11T14:21:44Z")

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Tell us how you _really_ feel, Phil. 😆