Kotlin class servlet provoke NoClassDefFoundError - kotlin

Question

In a sample Java servlet project in my IntelliJ IDE, i have created this class in Kotlin :
#WebServlet(name = "TwitterAPIServlet", description = "This is used to test the servlet api", urlPatterns = ["/twitterAPIServlet"])
class TwitterAPIServlet : HttpServlet() {
#Throws(IOException::class)
override fun doGet(req: HttpServletRequest, resp: HttpServletResponse) {
// Print answer
val out = resp.writer
out.println("Request Done : </br>")
}
}
When i am trying to call this with my .jsp page, i have this error :
2020-05-10 15:30:34.218:WARN:oejs.HttpChannel:qtp60559178-27: /twitterAPIServlet
java.lang.NoClassDefFoundError: kotlin/jvm/internal/Intrinsics
at main.java.co.rezo.api.internal.v1.TwitterAPIServlet.doGet(TwitterAPIServlet.kt)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
When i am trying the same code in Java, it's working :
#WebServlet(
name = "TwitterAPIServlet",
description = "This is used to test the servlet api",
urlPatterns = "/twitterAPIServlet")
public class TwitterAPIServlet extends HttpServlet {
#Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
PrintWriter out = resp.getWriter();
out.println("Request Done : </br>");
}
}
What can i do to make my Kotlin code working?

Answer 1

Most probably the issue is that Kotlin's standard library is not included in the generated WAR (or is not on a classpath if you run the exploded app). Make sure to include it in your build.
Instructions for Gradle can be found in the official examples repository: kotlin-examples.
Maven is similar: https://kotlinlang.org/docs/reference/using-maven.html.
In case of pure IDEA (though it's recommended to use one of the build tools above), check the projects settings:
You should see Kotlin's stdlib included in the artifact: