# Unrecognized VM option 'UseConcMarkSweepGC

**URL:** <https://discuss.elastic.co/t/unrecognized-vm-option-useconcmarksweepgc/254534>\
**Category:** Logstash\
**Created:** [November 6, 2020, 1:27pm UTC](https://discuss.elastic.co/t/unrecognized-vm-option-useconcmarksweepgc/254534 "2020-11-06T13:27:46Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![seePyou](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/seepyou/32/78554_2.png) [@seePyou](https://discuss.elastic.co/u/seePyou)\
**Post date:** [November 6, 2020, 1:27pm UTC](https://discuss.elastic.co/t/unrecognized-vm-option-useconcmarksweepgc/254534/1 "2020-11-06T13:27:46Z")

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Hello

I'm trying to use logstash in Windows 10 but I am stuck at this error:

```auto
PS C:\logstash-7.9.3\bin> .\logstash -e 'input {stdin{}} output {stdout{}}'
Unrecognized VM option 'UseConcMarkSweepGC'
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.

PS C:\logstash-7.9.3\bin> Write-Host $env:JAVA_HOME
C:\jdk-15.0.1

PS C:\logstash-7.9.3\bin> java -version
java version "1.8.0_271"
Java(TM) SE Runtime Environment (build 1.8.0_271-b09)
Java HotSpot(TM) 64-Bit Server VM (build 25.271-b09, mixed mode)

```

Can anyone help?

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<div class="post-metadata">

**Author:** ![wangqinghuan](https://avatars.discourse-cdn.com/v4/letter/w/d26b3c/32.png) [@wangqinghuan](https://discuss.elastic.co/u/wangqinghuan)\
**Post date:** [November 8, 2020, 6:19am UTC](https://discuss.elastic.co/t/unrecognized-vm-option-useconcmarksweepgc/254534/2 "2020-11-08T06:19:26Z")

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> [@seePyou](#):
>
> `VM option 'UseConcMarkSweepGC`

Jvm option UseConcMarkSweepGC has been removed as of Java 15. You could degrade your JDK.

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<div class="post-metadata">

**Author:** ![seePyou](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/seepyou/32/78554_2.png) [@seePyou](https://discuss.elastic.co/u/seePyou)\
**Post date:** [November 9, 2020, 8:30am UTC](https://discuss.elastic.co/t/unrecognized-vm-option-useconcmarksweepgc/254534/3 "2020-11-09T08:30:58Z")

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Isn't this something that should be included in the Logstash download page?

Right now it only says "Java 8 is required for Logstash 6.x and 5.x. " saying nothing for Logstash 7.x and the installation steps also make no mention of Java requirements.

Can I even run two JDK in one computer? ElasticSearch comes with JDK 15 provided in the .zip file, but Logstash, part of the ELK stack, does noot work with JDK 15?

Should I ignore the JDK in ElasticSearch and install ...what?

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<div class="post-metadata">

**Author:** ![Badger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/badger/32/25190_2.png) [@Badger](https://discuss.elastic.co/u/Badger)\
**Post date:** [November 9, 2020, 3:58pm UTC](https://discuss.elastic.co/t/unrecognized-vm-option-useconcmarksweepgc/254534/4 "2020-11-09T15:58:13Z")

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> [@seePyou](#):
>
> Can I even run two JDK in one computer?

Yes, you can.

You can also edit the logstash jvm.options file to remove the unsupported option.

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<div class="post-metadata">

**Author:** ![seePyou](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/seepyou/32/78554_2.png) [@seePyou](https://discuss.elastic.co/u/seePyou)\
**Post date:** [November 9, 2020, 4:37pm UTC](https://discuss.elastic.co/t/unrecognized-vm-option-useconcmarksweepgc/254534/5 "2020-11-09T16:37:47Z")

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Ok thank you.

I opted to uninstalling 15 and installing 8. Everything works off that now and it seems to be fine.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [December 7, 2020, 4:37pm UTC](https://discuss.elastic.co/t/unrecognized-vm-option-useconcmarksweepgc/254534/6 "2020-12-07T16:37:49Z")

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