# Java Errors

**URL:** <https://community.wowza.com/t/java-errors/47733>\
**Category:** Wowza Streaming Engine\
**Created:** [November 20, 2016, 5:59pm UTC](https://community.wowza.com/t/java-errors/47733 "2016-11-20T17:59:32Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Yosef\_Abdo](https://avatars.discourse-cdn.com/v4/letter/y/65b543/32.png) [@Yosef\_Abdo](https://community.wowza.com/u/Yosef_Abdo)\
**Post date:** [November 20, 2016, 5:59pm UTC](https://community.wowza.com/t/java-errors/47733/1 "2016-11-20T17:59:32Z")

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Hi guys,

Since the last few days, i see one error that printing itself every second on wowzaEngine error log file.

Sytem Information:

Wowza version - 4.3.0.02 (build 17246)

Java Information

Java Version

1.8.0\_60

Java VM Version

25.60-b23

Java Architecture

64

Java Name

Java HotSpot™ 64-Bit Server VM

Java Vendor

Oracle Corporation

Java Home

/usr/local/WowzaStreamingEngine-4.3.0/jre1.8.0\_60

Java Max Heap Size

9891MB

Error:

**ERROR server comment 2016-11-20 16:46:13 - - - - - 899668.714 - - - - - - - - ApplicationInstance.doWatchdog[mediaCasterStreams.doWatchdog] : java.util.ConcurrentModificationException|at java.util.HashMap$HashIterator.nextNode(HashMap.java:1429)|at java.util.HashMap$KeyIterator.next(HashMap.java:1453)|at com.wowza.wms.mediacaster.MediaCasterStreamValidator.onValidateMediaCastersStop(MediaCasterStreamValidator.java:274)|at com.wowza.wms.mediacaster.MediaCasterStreamMap.doWatchdog(MediaCasterStreamMap.java:146)|at com.wowza.wms.application.ApplicationInstance.doWatchdog(ApplicationInstance.java:2314)|**

I’ve 4 Wowza engines on 4 standalone servers, and this is happening on one of them.

Nothing was changed on the system.

I need to know 2 things please:

- How could this error impact the service?

- How do i fix it?

- What is the trigger of it?

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**Author:** ![Jermaine\_Hemby](https://avatars.discourse-cdn.com/v4/letter/j/82dd89/32.png) [@Jermaine\_Hemby](https://community.wowza.com/u/Jermaine_Hemby)\
**Post date:** [December 17, 2016, 10:43am UTC](https://community.wowza.com/t/java-errors/47733/2 "2016-12-17T10:43:42Z")

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Hello,

Thanks for contacting Wowza Forums!

For your issue, can you open a ticket [HERE](https://www.wowza.com/support/open-ticket)

Can you provide the following information for the server having the errors and at least one server with no issue and this will help us determine where the issue is? Also could you include the details mentioned here and explain your workflow from ingest to distribution?

Your logs in a .zip file, located here: [install-dir]/logs

Your conf folder in a .zip file, located here: [install-dir]/conf

[Helpful Article on creating a .zip file](https://www.wowza.com/docs/how-to-create-a-compressed-zip-file-in-windows-os-x-and-linux)

Regards,

Jermaine