Failed to find the generated JsonAdapter class for class de.stefanmedack.model.Article

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When I run app.kt, I got this error:

Exception in thread "main" java.lang.RuntimeException: Failed to find the generated JsonAdapter class for class de.stefanmedack.model.Article
	at com.squareup.moshi.internal.Util.generatedAdapter(Util.java:481)
	at com.squareup.moshi.StandardJsonAdapters$1.create(StandardJsonAdapters.java:60)
	at com.squareup.moshi.Moshi.nextAdapter(Moshi.java:168)
	at de.stefanmedack.adapter.DefaultOnDataMismatchAdapter$Companion$newFactory$1.create(DefaultOnDataMismatchAdapter.kt:35)
	at com.squareup.moshi.Moshi.adapter(Moshi.java:137)
	at com.squareup.moshi.Moshi.adapter(Moshi.java:97)
	at com.squareup.moshi.Moshi.adapter(Moshi.java:71)
	at de.stefanmedack.AppKt.printArticle(app.kt:11)
	at de.stefanmedack.AppKt.main(app.kt:7)
Caused by: java.lang.ClassNotFoundException: de.stefanmedack.model.ArticleJsonAdapter
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:348)
	at com.squareup.moshi.internal.Util.generatedAdapter(Util.java:467)
	... 8 more

I have got very similar error with my own sample project when I tried moshi code gen with IntelliJ, it was fine with Android Studio though. (I'm using IntelliJ 2018.3.3)

Do you have any idea why is this happening?