# Type mismatch error on injection **URL:** \ **Category:** Gatling (Open-Source)\ **Created:** [January 18, 2022, 11:44am UTC](https://community.gatling.io/t/type-mismatch-error-on-injection/6397 "2022-01-18T11:44:17Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Anna](https://avatars.discourse-cdn.com/v4/letter/a/779978/32.png) [@Anna](https://community.gatling.io/u/Anna)\ **Post date:** [January 18, 2022, 11:44am UTC](https://community.gatling.io/t/type-mismatch-error-on-injection/6397/1 "2022-01-18T11:44:17Z")
My code is as below. I seethat andThen is introduced in a later version. But when I use the below version, it doesnt run setUp( allScenarios50.inject(atOnceUsers(rampupUsers) ) .andThen( historicBidScenarios50.inject(atOnceUsers(rampupUsers) ) ) ).protocols(httpProtocol) with mvn plugin io.gatling gatling-maven-plugin 3.1.1 gives compilation error io.gatling.core.structure.PopulationBuilder required: io.gatling.commons.validation.Validation[io.gatling.core.structure.PopulationBuilder] =\> ? historicBidScenarios50.inject(atOnceUsers(rampupUsers) ) ---
**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:** [January 18, 2022, 11:52am UTC](https://community.gatling.io/t/type-mismatch-error-on-injection/6397/2 "2022-01-18T11:52:05Z")
The versions of the gatling-maven-plugin and of Gatling itself are unrelated. Please check your Gatling version. andThen was introduced in 3.4.0. ---
**Author:** ![Anna](https://avatars.discourse-cdn.com/v4/letter/a/779978/32.png) [@Anna](https://community.gatling.io/u/Anna)\ **Post date:** [January 18, 2022, 12:07pm UTC](https://community.gatling.io/t/type-mismatch-error-on-injection/6397/3 "2022-01-18T12:07:21Z")
Now I have added the dependency > io.gatling gatling-core 3.7.4 I get the error on other parts of code type mismatch; found : io.gatling.core.check.CheckBuilder.Final[io.gatling.core.check.jsonpath.JsonPathCheckType,com.fasterxml.jackson.databind.JsonNode] required: io.gatling.http.check.HttpCheck .check(jsonPath(“$[0].panelId”).is(“CUR”)) ---
**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:** [January 18, 2022, 12:25pm UTC](https://community.gatling.io/t/type-mismatch-error-on-injection/6397/4 "2022-01-18T12:25:03Z")
Sorry, it’s impossible to tell without you providing a full sample, eg a sample project on GitHub. Then, please note that since Gatling 3.7, Gatling also supports Java and Kotlin. I would recommend against starting a new Gatling project in Scala unless you’re a Scala developer. ---
**Author:** ![Anna](https://avatars.discourse-cdn.com/v4/letter/a/779978/32.png) [@Anna](https://community.gatling.io/u/Anna)\ **Post date:** [January 18, 2022, 12:38pm UTC](https://community.gatling.io/t/type-mismatch-error-on-injection/6397/5 "2022-01-18T12:38:08Z")
Now after adding scala plugin many errors vanished. The only error now is Symbol ‘type io.gatling.commons.shared.unstable.model.stats.assertion.AssertionPathParts’ is missing from the classpath. This symbol is required by ‘method io.gatling.core.assertion.AssertionSupport.string2PathParts’. Make sure that type AssertionPathParts is in your classpath and check for conflicting dependencies with `-Ylog-classpath`. A full rebuild may help if ‘AssertionSupport.class’ was compiled against an incompatible version of io.gatling.commons.shared.unstable.model.stats.assertion. val rampupUsers: Int = if(System.getProperty(“rampupUsers”) != null && System.getProperty(“rampupUsers”) != “”) System.getProperty(“rampupUsers”).toInt else 50 The sample code is **val usersFile: String = if(System.getProperty(“users”) != null && System.getProperty(“users”) != “”) System.getProperty(“users”) else "users.csv"** **val rampupUsers: Int = if(System.getProperty(“rampupUsers”) != null && System.getProperty(“rampupUsers”) != “”) System.getProperty(“rampupUsers”).toInt else 50** setUp( allScenarios.inject(atOnceUsers(rampupUsers) ) .andThen( historicScenarios.inject( rampUsers(rampupUsers) during (1 minute) ) ) I hope the sample is clear. I cannot share the whole in github, since beacuse of company regulations. Mvn dependencies are io.gatling gatling-core 3.5.0 net.alchim31.maven scala-maven-plugin 4.4.0 maven-plugin org.scala-lang scala-library 2.12.0 ---
**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:** [January 18, 2022, 12:43pm UTC](https://community.gatling.io/t/type-mismatch-error-on-injection/6397/6 "2022-01-18T12:43:14Z")
Really, why don’t you upgrade to Gatling 3.7.4 and switch to Java instead of Scala? > 2.12.0 This is wrong. Since Gatling 3.5, Gatling requires Scala 2.13. ---
**Author:** ![Anna](https://avatars.discourse-cdn.com/v4/letter/a/779978/32.png) [@Anna](https://community.gatling.io/u/Anna)\ **Post date:** [January 18, 2022, 12:48pm UTC](https://community.gatling.io/t/type-mismatch-error-on-injection/6397/7 "2022-01-18T12:48:05Z")
Now changed to 2.13.0 But the error persists ---
**Author:** ![Anna](https://avatars.discourse-cdn.com/v4/letter/a/779978/32.png) [@Anna](https://community.gatling.io/u/Anna)\ **Post date:** [January 18, 2022, 12:56pm UTC](https://community.gatling.io/t/type-mismatch-error-on-injection/6397/8 "2022-01-18T12:56:12Z")
Somehow it was the teams decision to use scala somehow. Now I need to live with this. I have no say in this. Hopeyou understand my helplessness