how to refresh jar file contents after contentsChanged event

hello,
I have encountered the following problem :
after an external library's contents have been changed, I detect a 'contentsChanged' event triggered for the library's jar archive.
But when I iterate over its children using the following code snippets :

...
VirtualFile jarClassRoot = StandardFileSystems.getJarRootForLocalFile(changedFile);
VfsUtilCore.visitChildrenRecursively(jarClassRoot, new VirtualFileVisitor() {
    @Override
    public boolean visitFile(@NotNull VirtualFile file) {
        if (!file.isDirectory()) {
            if (isAcceptedInputFile(file)) {   // child file recognized as potentialy interesting
                structureDefFiles.add(fil);   // add it to the interesting file collection..
            }
            return false;  // move to the next sibling
        }
        return true;  // iterate over directory's contents 
    }
});
...
 

I get the same file list as before 'contentsChanged' event (meaning a refresh is needed..)
How to force IDEA to refresh the changed jar's contents ?
Do I need to explicitly call

jarClassRoot.refresh(false, true)

from within a writeAction (synchronous call) to make it happen ?
Or should I wait for 'start' mode (if it has something to do with file-based indices..)
I would be very grateful for a more elaborate description of how jar archives are handled by IDEA (I couldn't figure it out on my own) and how to properly recognize a file as a jar archive (i use file extension for this purpose as I haven't found any dedicated file type - there's only some generic 'ARCHIVE' type)
Thank you in advance for any feedback,
regards
Simon