This test configures a FileSystemProvider that interposes over the otherwise default provider. This leads to a recursive initialization issue during startup because the file system provider is located via the system class loader. Here's the output of the test when run with a build of jigsaw/m2:

command: main -Djava.nio.file.spi.DefaultFileSystemProvider=TestProvider SetDefaultProvider
reason: User specified action: run main/othervm -Djava.nio.file.spi.DefaultFileSystemProvider=TestProvider SetDefaultProvider
elapsed time (seconds): 0.277
----------System.out:(0/0)----------
----------System.err:(51/3169)----------
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.Error: java.lang.NullPointerException
at java.nio.file.FileSystems$DefaultFileSystemHolder.getDefaultProvider(FileSystems.java:128)
at java.nio.file.FileSystems$DefaultFileSystemHolder.access$000(FileSystems.java:89)
at java.nio.file.FileSystems$DefaultFileSystemHolder$1.run(FileSystems.java:98)
at java.nio.file.FileSystems$DefaultFileSystemHolder$1.run(FileSystems.java:96)
at java.security.AccessController.doPrivileged(Native Method)
at java.nio.file.FileSystems$DefaultFileSystemHolder.defaultFileSystem(FileSystems.java:96)
at java.nio.file.FileSystems$DefaultFileSystemHolder.<clinit>(FileSystems.java:90)
at java.nio.file.FileSystems.getDefault(FileSystems.java:176)
at java.io.File.toPath(File.java:2236)
at jdk.internal.jimage.ImageReader.open(ImageReader.java:71)
at sun.misc.JImageCache.get(JImageCache.java:74)
at sun.misc.URLClassPath$JImageLoader.<init>(URLClassPath.java:1120)
at sun.misc.URLClassPath$3.run(URLClassPath.java:373)
at sun.misc.URLClassPath$3.run(URLClassPath.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at sun.misc.URLClassPath.getLoader(URLClassPath.java:360)
at sun.misc.URLClassPath.getLoader(URLClassPath.java:337)
at sun.misc.URLClassPath.getResource(URLClassPath.java:203)
at java.net.URLClassLoader$1.run(URLClassLoader.java:365)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:426)
at java.lang.ClassLoader.loadClass(ClassLoader.java:413)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:359)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:504)
Caused by: java.lang.NullPointerException
at java.io.File.toPath(File.java:2236)
at jdk.internal.jimage.ImageReader.open(ImageReader.java:71)
at sun.misc.JImageCache.get(JImageCache.java:74)
at sun.misc.URLClassPath$JImageLoader.<init>(URLClassPath.java:1120)
at sun.misc.URLClassPath$3.run(URLClassPath.java:373)
at sun.misc.URLClassPath$3.run(URLClassPath.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at sun.misc.URLClassPath.getLoader(URLClassPath.java:360)
at sun.misc.URLClassPath.getLoader(URLClassPath.java:337)
at sun.misc.URLClassPath.getResource(URLClassPath.java:203)
at java.net.URLClassLoader$1.run(URLClassLoader.java:365)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:426)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:359)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:346)
at java.nio.file.FileSystems$DefaultFileSystemHolder.getDefaultProvider(FileSystems.java:118)
... 26 more

This issue is going to be tricky to resolve.