The default, built-in filename map in the JDK has been updated to include additional filename to MIME type mappings. Along with the additions, existing mappings of `.gz` and `.zip` have also been updated. This can result in the default, built-in `java.net.FileNameMap` instance returning a different MIME type from the `getContentTypeFor(String fileName)` method than what it returned in previous JDK releases.

`java.net.URLConnection.guessContentTypeFromName(String fname)`, which may use this default, built-in `FileNameMap` instance, thus may return a different value than previously.