Grammar-kit + Kotlin: How to define custom adapt_builder_ from GeneratedParserUtilBase in own ParserUtil?

Hi,

I'm trying to implement custom language plugin with Grammr-kit and Kotlin. I need to implement my own ParserUtil class based on GeneratedParserUtilBase but also I need to define custom adapt_builder_ where I can save parser state for newly created builder. In other words I need to hook builder creation and run my code. In java it can be done easily:

public class JFlexParserUtil extends GeneratedParserUtilBase {

  public static PsiBuilder adapt_builder_(IElementType root, PsiBuilder builder, PsiParser parser, TokenSet[] extendsSets) {

    PsiBuilder result = GeneratedParserUtilBase.adapt_builder_(root, builder, parser, extendsSets);

<< run my code >>

  }

}

But how to implement adapt_builder_ in Kotlin? When I convert java code above to Kotlin code I receive `Accidental override: The following declarations have the same JVM signature`.

Is there another way to "hook" builder creation?