# Java: NoClassDefFoundException

**URL:** <https://community.openems.io/t/java-noclassdeffoundexception/2676>\
**Category:** English Forum\
**Created:** [May 19, 2024, 4:05am UTC](https://community.openems.io/t/java-noclassdeffoundexception/2676 "2024-05-19T04:05:20Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![spg1101](https://community.openems.io/letter_avatar_proxy/v4/letter/s/8491ac/32.png) [@spg1101](https://community.openems.io/u/spg1101)\
**Post date:** [May 19, 2024, 4:05am UTC](https://community.openems.io/t/java-noclassdeffoundexception/2676/1 "2024-05-19T04:05:20Z")

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Hello. My name is Jihoon Sim.

When I run OpenEMS project in Eclipse for Windows,  
([GitHub - OpenEMS/openems: OpenEMS - Open Source Energy Management System](https://github.com/OpenEMS/openems))  
some errors occur as images below. Is there anything else I have to set additionally?

![1](https://community.openems.io/uploads/default/original/2X/d/d7ce6fbd6582543b48356eb6c87c9fe8a038a84c.png)

Specifically, I followed the steps exactly on the website below.  
[https://openems.github.io/openems.io/openems/latest/gettingstarted.html](https://openems.github.io/openems.io/openems/latest/gettingstarted.html)

I followed the steps up to ‘3-1-a’ and pressed the button ‘Run OSGi’. But some errors occurred (Java: NoClassDefFoundException).  
I think I missed some settings, but I am wondering if you know anything.

I am looking forward to receiving your reply.  
Thanks for your reading.

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<div class="post-metadata">

**Author:** ![Sn0w3y](https://community.openems.io/user_avatar/community.openems.io/sn0w3y/32/636_2.png) [@Sn0w3y](https://community.openems.io/u/Sn0w3y)\
**Post date:** [May 20, 2024, 9:00am UTC](https://community.openems.io/t/java-noclassdeffoundexception/2676/2 "2024-05-20T09:00:50Z")

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close IDE restart, resolve bundles

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**Author:** ![stefan.feilmeier](https://community.openems.io/user_avatar/community.openems.io/stefan.feilmeier/32/2585_2.png) [@stefan.feilmeier](https://community.openems.io/u/stefan.feilmeier)\
**Post date:** [May 31, 2024, 10:49pm UTC](https://community.openems.io/t/java-noclassdeffoundexception/2676/3 "2024-05-31T22:49:20Z")

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Hi @spg1101 and welcome to the Community.

Usually these errors should only rarely happen during development. Please try to follow the steps listed here to fix them:

> [@Build in Eclipse fails with many errors](https://community.openems.io/t/build-in-eclipse-fails-with-many-errors/263/2):
>
> Hi, yes… this can happen from time to time. Most likely Eclipse did not recognize latest file changes. Here are some tips to get rid of build errors in Eclipse: Select all bundles in “Bndtools Explorer” (Ctrl + A) and press F5 to refresh them. This helps, if Eclipse did not recognize no files in existing bundles. Open File → Import in the menu and select Bndtools → Existing Bnd Workspace to reimport all bundles This helps, if there were new bundles added in the meantime. Those are not …

Regards,  
Stefan