# gatling-sbtNoClassDefFoundError

**URL:** <https://community.gatling.io/t/gatling-sbtnoclassdeffounderror/1534>\
**Category:** Gatling (Open-Source)\
**Created:** [October 13, 2014, 10:25am UTC](https://community.gatling.io/t/gatling-sbtnoclassdeffounderror/1534 "2014-10-13T10:25:38Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Jean-Yves\_LEBLEU](https://avatars.discourse-cdn.com/v4/letter/j/8e7dd6/32.png) [@Jean-Yves\_LEBLEU](https://community.gatling.io/u/Jean-Yves_LEBLEU)\
**Post date:** [October 13, 2014, 10:25am UTC](https://community.gatling.io/t/gatling-sbtnoclassdeffounderror/1534/1 "2014-10-13T10:25:38Z")

</div>

Hello all,

I did a small project to use gatling with sbt using the sbt plugin

can be found here [https://gitlab.com/jlebleu/gatlingxuc](https://gitlab.com/jlebleu/gatlingxuc)

Always have a NoClassDefFondEffor, and I can find what is my mistake.

If anyboday has an idea ?  
Thanks

Here is the trace

[error] Uncaught exception when running computerdatabase.BasicSimulation: java.lang.NoClassDefFoundError: scala/collection/GenTraversableOnce$class  
sbt.ForkMain$ForkError: scala/collection/GenTraversableOnce$class  
at com.dongxiguo.fastring.Fastring.(Fastring.scala:25)  
at io.gatling.core.util.StringHelper$$anon$1.(StringHelper.scala:53)  
at io.gatling.core.util.StringHelper$.(StringHelper.scala:53)  
at io.gatling.core.util.StringHelper$.(StringHelper.scala)  
at io.gatling.core.config.GatlingConfiguration$.mapToGatlingConfig(GatlingConfiguration.scala:134)  
at io.gatling.core.config.GatlingConfiguration$.setUp(GatlingConfiguration.scala:128)  
at io.gatling.app.Gatling$.fromMap(Gatling.scala:54)  
at io.gatling.app.Gatling$.runGatling(Gatling.scala:80)  
at io.gatling.sbt.GatlingTask.liftedTree1$1(GatlingTask.scala:34)  
at io.gatling.sbt.GatlingTask.execute(GatlingTask.scala:33)  
at sbt.ForkMain$Run$2.call(ForkMain.java:294)  
at sbt.ForkMain$Run$2.call(ForkMain.java:284)  
at java.util.concurrent.FutureTask.run(FutureTask.java:262)  
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)  
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)  
at java.lang.Thread.run(Thread.java:745)  
Caused by: sbt.ForkMain$ForkError: scala.collection.GenTraversableOnce$class  
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)  
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)  
at java.security.AccessController.doPrivileged(Native Method)  
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)  
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)  
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)  
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)  
at com.dongxiguo.fastring.Fastring.(Fastring.scala:25)  
at io.gatling.core.util.StringHelper$$anon$1.(StringHelper.scala:53)  
at io.gatling.core.util.StringHelper$.(StringHelper.scala:53)  
at io.gatling.core.util.StringHelper$.(StringHelper.scala)  
at io.gatling.core.config.GatlingConfiguration$.mapToGatlingConfig(GatlingConfiguration.scala:134)  
at io.gatling.core.config.GatlingConfiguration$.setUp(GatlingConfiguration.scala:128)  
at io.gatling.app.Gatling$.fromMap(Gatling.scala:54)  
at io.gatling.app.Gatling$.runGatling(Gatling.scala:80)  
at io.gatling.sbt.GatlingTask.liftedTree1$1(GatlingTask.scala:34)  
at io.gatling.sbt.GatlingTask.execute(GatlingTask.scala:33)  
at sbt.ForkMain$Run$2.call(ForkMain.java:294)  
at sbt.ForkMain$Run$2.call(ForkMain.java:284)  
at java.util.concurrent.FutureTask.run(FutureTask.java:262)  
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)  
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)  
at java.lang.Thread.run(Thread.java:745)

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<div class="post-metadata">

**Author:** ![Pierre\_DAL-PRA](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@Pierre\_DAL-PRA](https://community.gatling.io/u/Pierre_DAL-PRA)\
**Post date:** [October 13, 2014, 10:30am UTC](https://community.gatling.io/t/gatling-sbtnoclassdeffounderror/1534/2 "2014-10-13T10:30:43Z")

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Hi Jean-Yves,

That is your mistake : [https://gitlab.com/jlebleu/gatlingxuc/blob/master/project/Dependencies.scala#L22](https://gitlab.com/jlebleu/gatlingxuc/blob/master/project/Dependencies.scala#L22)  
Gatling currently relies and is not cross-compiled (due to your our current use and integration of Zinc, SBT’s incremental compiler). Having both scala-library for 2.10 and 2.11 in the classpath is sure to cause issues like that.  
Set your scalaVersion to “2.10.4” and it should work as expected.

Cheers,

Pierre

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<div class="post-metadata">

**Author:** ![Jean-Yves\_LEBLEU](https://avatars.discourse-cdn.com/v4/letter/j/8e7dd6/32.png) [@Jean-Yves\_LEBLEU](https://community.gatling.io/u/Jean-Yves_LEBLEU)\
**Post date:** [October 13, 2014, 12:29pm UTC](https://community.gatling.io/t/gatling-sbtnoclassdeffounderror/1534/3 "2014-10-13T12:29:46Z")

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Hi Pierre,

Thank you very much !!!  
Working now … as expected.  
Rgds.  
Jean-Yves