Error compiling in IntelliJ IDEA: “No MessageCollector”

Promoting the answer in the comments to an answer, because it’s the actual answer: This appears to be a bug in the IntelliJ Kotlin plugin v1.2.40 and how it interacts with Java 10. See here. The solution is to upgrade to v1.2.41. (Don’t switch your project to building with Gradle like the other answer suggests … Read more

Not annotated parameter overrides @??? parameter

Explanation Although I can’t reproduce this on AbstractItemCountingItemStreamItemReader from this artifact implementation group: ‘org.springframework.batch’, name: ‘spring-batch-core’, version: ‘4.1.2.RELEASE’ , this annotation means that the parent method has some @NotNull / @NonNull annotation on the parameter, while the overriding method has no. To fix it, you need to put the same annotation on the overriding method. … Read more

When would I use the “Mark directory as …” option in IntelliJ IDEA?

Lets go through the options: Sources Root – this is where your actual project code goes – typically in src/main/scala (though you can change that, or add extra source directories in your build). Directories nested below this level should be packages. Intellij needs to know these are sources so it can highlight them, check them … Read more