The function nsk_null_string test/hotspot/jtreg/vmTestbase/nsk/share/native/nsk_tools.hpp prints "<NULL>" when the argument is a null pointer. The comment describing the function includes that literal string. This interferes with searching HotSpot code for uses of NULL, which is forbidden. An exception could be made for this case, but it might be simpler to change the printed string for that case.