Consider the following:
var uri = URI.create("jrt:/java.base/module-info.class");
var path = Path.of(uri);
assertTrue(Files.exists(path));
This fails because the file path returned by JrtFIleSystemProvider getPath(URI) is "/java.base/module-info.class", it should be "/modules/java.base/module-info.class".
If this bug is fixed then the following round trip should also work:
// check round-trip
var jrtfs = FileSystems.getFileSystem(URI.create("jrt:/"));
assertTrue(Files.exists(jrtfs.getPath(path.toString())));