Ooops !
if you use the module path, you can not change the default system provider
mechanism anymore,
mostly because the module implementation internally uses java.nio.file.Path at
different places.
First, trying to initialize the default system provider in Java code do not
work at all,
calling
System.setProperty("java.nio.file.spi.DefaultFileSystemProvider", "...");
in a main does nothing because the jigsaw implementation has already loaded the
default implementation to be able to inspect the modules.
Then, if you try to use the command line
-Djava.nio.file.spi.DefaultFileSystemProvider=...
you have various bootstrapping issues.
With exploded modules, when trying to initialize the default file system, the
part of jigsaw that reads exploded modules uses path.toFile() that fails it
checks that the path belongs to the default file system which is not already
initialized
(see below for the whole stacktrace)
With modular jars, when trying to initialize the default file system, the
JarModuleReader also uses path.toFile(), leading to the same error
One way to solve that is to change the code in FileSystems.getDefault() to add
a nullcheck,
FileSystem defaultFileSystem =
DefaultFileSystemHolder.defaultFileSystem;
if (jdk.internal.misc.VM.isBooted() && defaultFileSystem != null) {
return defaultFileSystem;
} else {
return BuiltinFileSystemHolder.builtinFileSystem;
}
Another solution is to change the code of jigsaw to only use the
builtinFileSystem, delaying the initialization of the default system which will
also solve the case where an application uses System.setProperty.
cheers,
Rémi
Stacktrace with exploded modules:
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.Error:
java.lang.UnsupportedOperationException: Path not associated with default file
system.
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder.getDefaultProvider(FileSystems.java:139)
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder.access$100(FileSystems.java:100)
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder$1.run(FileSystems.java:109)
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder$1.run(FileSystems.java:107)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder.defaultFileSystem(FileSystems.java:107)
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder.<clinit>(FileSystems.java:101)
at java.base/java.nio.file.FileSystems.getDefault(FileSystems.java:188)
at java.base/java.nio.file.Path.toFile(Path.java:655)
at
java.base/jdk.internal.module.ModuleReferences$JarModuleReader.newJarFile(ModuleReferences.java:229)
at
java.base/jdk.internal.module.ModuleReferences$JarModuleReader.<init>(ModuleReferences.java:239)
at
java.base/jdk.internal.module.ModuleReferences.lambda$newJarModule$0(ModuleReferences.java:96)
at
java.base/jdk.internal.module.ModuleReferenceImpl.open(ModuleReferenceImpl.java:88)
at
java.base/jdk.internal.loader.BuiltinClassLoader.createModuleReader(BuiltinClassLoader.java:953)
at
java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1719)
at
java.base/jdk.internal.loader.BuiltinClassLoader.moduleReaderFor(BuiltinClassLoader.java:945)
at
java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:702)
at
java.base/jdk.internal.loader.BuiltinClassLoader.findClassInModuleOrNull(BuiltinClassLoader.java:651)
at
java.base/jdk.internal.loader.BuiltinClassLoader.findClass(BuiltinClassLoader.java:532)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:585)
at java.base/java.lang.Class.forName(Class.java:447)
at
java.base/sun.launcher.LauncherHelper.loadModuleMainClass(LauncherHelper.java:585)
at
java.base/sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:523)
Caused by: java.lang.UnsupportedOperationException: Path not associated with
default file system.
at java.base/java.nio.file.Path.toFile(Path.java:658)
at
java.base/jdk.internal.module.ModuleReferences$JarModuleReader.newJarFile(ModuleReferences.java:229)
at
java.base/jdk.internal.module.ModuleReferences$JarModuleReader.<init>(ModuleReferences.java:239)
at
java.base/jdk.internal.module.ModuleReferences.lambda$newJarModule$0(ModuleReferences.java:96)
at
java.base/jdk.internal.module.ModuleReferenceImpl.open(ModuleReferenceImpl.java:88)
at
java.base/jdk.internal.loader.BuiltinClassLoader.createModuleReader(BuiltinClassLoader.java:953)
at
java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1719)
at
java.base/jdk.internal.loader.BuiltinClassLoader.moduleReaderFor(BuiltinClassLoader.java:945)
at
java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:702)
at
java.base/jdk.internal.loader.BuiltinClassLoader.findClassInModuleOrNull(BuiltinClassLoader.java:651)
at
java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:576)
at
java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:550)
at
java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:185)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:473)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:374)
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder.getDefaultProvider(FileSystems.java:129)
... 22 more
StackTrace with modular jars:
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.Error:
java.lang.UnsupportedOperationException: Path not associated with default file
system.
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder.getDefaultProvider(FileSystems.java:139)
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder.access$100(FileSystems.java:100)
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder$1.run(FileSystems.java:109)
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder$1.run(FileSystems.java:107)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder.defaultFileSystem(FileSystems.java:107)
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder.<clinit>(FileSystems.java:101)
at java.base/java.nio.file.FileSystems.getDefault(FileSystems.java:188)
at java.base/java.nio.file.Path.toFile(Path.java:655)
at
java.base/jdk.internal.module.ModuleReferences$JarModuleReader.newJarFile(ModuleReferences.java:229)
at
java.base/jdk.internal.module.ModuleReferences$JarModuleReader.<init>(ModuleReferences.java:239)
at
java.base/jdk.internal.module.ModuleReferences.lambda$newJarModule$0(ModuleReferences.java:96)
at
java.base/jdk.internal.module.ModuleReferenceImpl.open(ModuleReferenceImpl.java:88)
at
java.base/jdk.internal.loader.BuiltinClassLoader.createModuleReader(BuiltinClassLoader.java:953)
at
java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1719)
at
java.base/jdk.internal.loader.BuiltinClassLoader.moduleReaderFor(BuiltinClassLoader.java:945)
at
java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:702)
at
java.base/jdk.internal.loader.BuiltinClassLoader.findClassInModuleOrNull(BuiltinClassLoader.java:651)
at
java.base/jdk.internal.loader.BuiltinClassLoader.findClass(BuiltinClassLoader.java:532)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:585)
at java.base/java.lang.Class.forName(Class.java:447)
at
java.base/sun.launcher.LauncherHelper.loadModuleMainClass(LauncherHelper.java:585)
at
java.base/sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:523)
Caused by: java.lang.UnsupportedOperationException: Path not associated with
default file system.
at java.base/java.nio.file.Path.toFile(Path.java:658)
at
java.base/jdk.internal.module.ModuleReferences$JarModuleReader.newJarFile(ModuleReferences.java:229)
at
java.base/jdk.internal.module.ModuleReferences$JarModuleReader.<init>(ModuleReferences.java:239)
at
java.base/jdk.internal.module.ModuleReferences.lambda$newJarModule$0(ModuleReferences.java:96)
at
java.base/jdk.internal.module.ModuleReferenceImpl.open(ModuleReferenceImpl.java:88)
at
java.base/jdk.internal.loader.BuiltinClassLoader.createModuleReader(BuiltinClassLoader.java:953)
at
java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1719)
at
java.base/jdk.internal.loader.BuiltinClassLoader.moduleReaderFor(BuiltinClassLoader.java:945)
at
java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:702)
at
java.base/jdk.internal.loader.BuiltinClassLoader.findClassInModuleOrNull(BuiltinClassLoader.java:651)
at
java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:576)
at
java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:550)
at
java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:185)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:473)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:374)
at
java.base/java.nio.file.FileSystems$DefaultFileSystemHolder.getDefaultProvider(FileSystems.java:129)
... 22 more
