# 2.2.0-M3 -\> 2.2.0-SNAPSHOT regression: NPE when using proxy

**URL:** <https://community.gatling.io/t/2-2-0-m3-2-2-0-snapshot-regression-npe-when-using-proxy/2657>\
**Category:** Gatling (Open-Source)\
**Created:** [November 4, 2015, 6:57pm UTC](https://community.gatling.io/t/2-2-0-m3-2-2-0-snapshot-regression-npe-when-using-proxy/2657 "2015-11-04T18:57:25Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Dragos\_Manolescu](https://avatars.discourse-cdn.com/v4/letter/d/45deac/32.png) [@Dragos\_Manolescu](https://community.gatling.io/u/Dragos_Manolescu)\
**Post date:** [November 4, 2015, 6:57pm UTC](https://community.gatling.io/t/2-2-0-m3-2-2-0-snapshot-regression-npe-when-using-proxy/2657/1 "2015-11-04T18:57:25Z")

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Greetings –

I switched from 2.2.0-M3 to 2.2.0-SNAPSHOT. The (few) user-visible API changes were easy to deal with (e.g., io.gatling.core.validation.Success → io.gatling.commons.validation.Success). However I ran into unexpected behavior that looks like a bug; here’s the relevant code fragment:

val pb = http  
.proxy(Proxy(“localhost”, 8888))  
.baseURL(endpoint)

// etc.

The simulation works fine with the proxy line commented out; bringing it in generates a NPE:

error] java.lang.NullPointerException: principal  
[error] at org.asynchttpclient.util.Assertions.assertNotNull(Assertions.java:23)  
[error] at org.asynchttpclient.Realm.(Realm.java:71)  
[error] at org.asynchttpclient.Realm.(Realm.java:37)  
[error] at org.asynchttpclient.Realm$Builder.build(Realm.java:497)  
[error] at io.gatling.http.ahc.package$ProxyConverter$.proxyServer$extension(package.scala:32)  
[error] at io.gatling.http.protocol.HttpProtocolBuilder.proxy(HttpProtocolBuilder.scala:129)  
[error] at eg.CalypsoSimulation.(simulations.scala:26)  
[error] at eg.EventSimulation.(simulations.scala:63)  
[error] at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)  
[error] at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)  
[error] at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)  
[error] at java.lang.reflect.Constructor.newInstance(Constructor.java:422)  
[error] at java.lang.Class.newInstance(Class.java:442)  
[error] at io.gatling.app.Gatling.run(Gatling.scala:87)  
[error] at io.gatling.app.Gatling.runIfNecessary(Gatling.scala:70)  
[error] at io.gatling.app.Gatling.start(Gatling.scala:60)  
[error] at io.gatling.app.Gatling$.start(Gatling.scala:51)  
[error] at io.gatling.app.Gatling$.fromArgs(Gatling.scala:43)  
[error] at io.gatling.sbt.GatlingTask.liftedTree1$1(GatlingTask.scala:51)  
[error] at io.gatling.sbt.GatlingTask.execute(GatlingTask.scala:50)  
[error] at sbt.ForkMain$Run$2.call(ForkMain.java:296)  
[error] at sbt.ForkMain$Run$2.call(ForkMain.java:286)  
[error] at java.util.concurrent.FutureTask.run(FutureTask.java:266)  
[error] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)  
[error] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)  
[error] at java.lang.Thread.run(Thread.java:745)  
[error] Simulation EventSimulation failed.

If it matters I run the simulation via the sbt plugin.

Thanks,

-Dragos

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<div class="post-metadata">

**Author:** ![slandelle](https://dub1.discourse-cdn.com/flex013/user_avatar/community.gatling.io/slandelle/32/4_2.png) [@slandelle](https://community.gatling.io/u/slandelle)\
**Post date:** [November 4, 2015, 7:39pm UTC](https://community.gatling.io/t/2-2-0-m3-2-2-0-snapshot-regression-npe-when-using-proxy/2657/2 "2015-11-04T19:39:40Z")

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Fixed, thanks for reporting