I tried to run Sample.java in JDK-8236161 with -Dfile.encoding=UTF-8, but JVM crashed due to internal error on fastdebug VM. I saw same call stack with JDK-8236161 in hs_err log.
I investigated it, then I found out current implementation cannot handle default charset.
If charset is set to UTF-8, it would be handled as "DEFAULT_CHARSET" in WFontConfiguration::initTables. However it does not affect native font name, so we cannot find valid font.