UserDefinedFileAttributeView view returns null , unable to set attributes

Question

I am trying to tag files on an android device to display later on a list based on user defined tags (e.g. Category , Description , Owner). I have used the widely recommended java NIO code for UserDefinedFileAttributes

The file path is found and is reported as valid , however

final UserDefinedFileAttributeView view = getFileAttributeView (path, 
UserDefinedFileAttributeView.class); 

always returns 'view' = null

What am I missing?

Perhaps UserDefinedFileAttributeView is not supported on all platforms / devices? I have tried this code on Android Studio emulator for Nexus 6 (API 28)

String MEDIA_PATH = Environment.getExternalStorageDirectory().getPath()
                   + File.separator + "myEMR" + File.separator + 
                    "Imported_Documents" ;
String uNewFileName = "MyFile";

public void setLocalFileAttributes() throws Exception {

    Path path = Paths.get(MEDIA_PATH, uNewFileName);

    final UserDefinedFileAttributeView view = getFileAttributeView(path, 
          UserDefinedFileAttributeView.class);

    // The file attribute
    final String category = "Category";
    final String value = "UnCategorised";


  final byte[] bytes = value.getBytes("UTF-8");
        final ByteBuffer writeBuffer = 
        ByteBuffer.allocate(bytes.length);
        writeBuffer.put(bytes);
        writeBuffer.flip();
        view.write(category, writeBuffer);

}