8346722: (fs) Files.probeContentType throws ClassCastException with custom file system provider

Reviewed-by: alanb

Author: Brian Burkhalter

src/java.base/unix/classes/sun/nio/fs/DefaultFileTypeDetector.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,15 +25,12 @@
 
 package sun.nio.fs;
 
-import java.nio.file.FileSystems;
 import java.nio.file.spi.FileTypeDetector;
-import java.nio.file.spi.FileSystemProvider;
 
 public class DefaultFileTypeDetector {
     private DefaultFileTypeDetector() { }
 
     public static FileTypeDetector create() {
-        FileSystemProvider provider = FileSystems.getDefault().provider();
-        return ((UnixFileSystemProvider)provider).getFileTypeDetector();
+        return DefaultFileSystemProvider.instance().getFileTypeDetector();
     }
 }

test/jdk/java/nio/file/spi/SetDefaultProvider.java

@@ -23,7 +23,8 @@
 
 /*
  * @test
- * @bug 4313887 7006126 8142968 8178380 8183320 8210112 8266345 8263940 8331467 8346573
+ * @bug 4313887 7006126 8142968 8178380 8183320 8210112 8266345 8263940 8331467
+ *      8346573 8346722
  * @modules jdk.jartool jdk.jlink
  * @library /test/lib
  * @build testfsp/* testapp/* CustomSystemClassLoader

test/jdk/java/nio/file/spi/testapp/testapp/Main.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -58,5 +58,8 @@ public static void main(String[] args) throws Exception {
             throw new RuntimeException("'path' not in default file system");
         if (!path.equals(foo))
             throw new RuntimeException(path + " not equal to " + foo);
+
+        // exercise the file type detector
+        String fileType = Files.probeContentType(Path.of("."));
     }
 }