As noted in CSR JDK-8230044, the ProxySelector.select method's API expectations have been updated to have it throw an IllegalArgumentException when the host or protocol cannot be determined from the URI that's passed to it.

The patch contributed as part of JDK-8177648 took care of this usage in certain places like the sun/net/www/protocol/http/HttpURLConnection.java and the sun/net/www/protocol/ftp/FtpURLConnection.java. It was decided to update the rest of the usages separately, on a case by case basis.

java.net.SocksSocketImpl is one such place where such an update seems relevant.