JDK-7133476 : (fs) Files.readAttributes throws NPE on MacOSX
  • Type: Bug
  • Component: core-libs
  • Sub-Component: java.nio
  • Affected Version: 7u4
  • Priority: P4
  • Status: Closed
  • Resolution: Fixed
  • OS: os_x
  • CPU: x86
  • Submitted: 2012-01-26
  • Updated: 2012-03-27
  • Resolved: 2012-03-27
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JDK 7
7u4 b11Fixed
Description
From http://java.net/jira/browse/MACOSX_PORT-133 --

java.nio.file.Files .readAttributes throws NPE on MacOS

Simple test case:
import java.nio.file.attribute.DosFileAttributes;
import java.nio.ByteBuffer;
import java.nio.channels.SeekableByteChannel;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import static java.nio.file.StandardOpenOption.*;

public class Test {
public static void main(String argv[]) {
Path path = Paths.get("temp.txt");
String data = "Hello world!";
SeekableByteChannel sbc = null;

try { ByteBuffer bb = ByteBuffer.wrap(data.getBytes()); sbc = Files.newByteChannel(path, CREATE, WRITE); sbc.write(bb); DosFileAttributes dfa = null; dfa = Files.readAttributes(path, DosFileAttributes.class); } catch (Exception e) { e.printStackTrace(); }
}

}

Test output:

Exception in thread "main" java.lang.NullPointerException
at sun.nio.fs.BsdFileSystemProvider.readAttributes(BsdFileSystemProvider.java:78)
at java.nio.file.Files.readAttributes(Files.java:1669)
at TestCopy01.test01(TestCopy01.java:85)
at TestCopy01.main(TestCopy01.java:37)
Comments
EVALUATION See comments, most of sun.nio.fs.Bsd* should be removed,
26-01-2012
SUGGESTED FIX There is no need for BsdFileSystemProvider to override readAttributes. In addition, most of sun.nio.fs.Bsd* can be removed - is is just not needed. diff --git a/src/solaris/classes/sun/nio/fs/BsdFileStore.java b/src/solaris/classes/sun/nio/fs/BsdFileStore.java --- a/src/solaris/classes/sun/nio/fs/BsdFileStore.java +++ b/src/solaris/classes/sun/nio/fs/BsdFileStore.java @@ -85,76 +85,4 @@ throw new IOException("Mount point not found in fstab"); } - - // returns true if extended attributes enabled on file system where given - // file resides, returns false if disabled or unable to determine. - private boolean isExtendedAttributesEnabled(UnixPath path) { -/* - try { - int fd = path.openForAttributeAccess(false); - try { - // fgetxattr returns size if called with size==0 - BsdNativeDispatcher.fgetxattr(fd, "user.java".getBytes(), 0L, 0); - return true; - } catch (UnixException e) { - // attribute does not exist - if (e.errno() == UnixConstants.ENODATA) - return true; - } finally { - UnixNativeDispatcher.close(fd); - } - } catch (IOException ignore) { - // nothing we can do - } -*/ - return false; - } - - @Override - public boolean supportsFileAttributeView(Class<? extends FileAttributeView> type) { -/* - // support DosFileAttributeView and UserDefinedAttributeView if extended - // attributes enabled - if (type == DosFileAttributeView.class || - type == UserDefinedFileAttributeView.class) - { - // lookup fstypes.properties - FeatureStatus status = checkIfFeaturePresent("user_xattr"); - if (status == FeatureStatus.PRESENT) - return true; - if (status == FeatureStatus.NOT_PRESENT) - return false; - - // if file system is mounted with user_xattr option then assume - // extended attributes are enabled - if ((entry().hasOption("user_xattr"))) - return true; - - // user_xattr option not present but we special-case ext3/4 as we - // know that extended attributes are not enabled by default. - if (entry().fstype().equals("ext3") || entry().fstype().equals("ext4")) - return false; - - // not ext3/4 so probe mount point - if (!xattrChecked) { - UnixPath dir = new UnixPath(file().getFileSystem(), entry().dir()); - xattrEnabled = isExtendedAttributesEnabled(dir); - xattrChecked = true; - } - return xattrEnabled; - } -*/ - return super.supportsFileAttributeView(type); - } - - @Override - public boolean supportsFileAttributeView(String name) { -/* - if (name.equals("dos")) - return supportsFileAttributeView(DosFileAttributeView.class); - if (name.equals("user")) - return supportsFileAttributeView(UserDefinedFileAttributeView.class); -*/ - return super.supportsFileAttributeView(name); - } } diff --git a/src/solaris/classes/sun/nio/fs/BsdFileSystemProvider.java b/src/solaris/classes/sun/nio/fs/BsdFileSystemProvider.java --- a/src/solaris/classes/sun/nio/fs/BsdFileSystemProvider.java +++ b/src/solaris/classes/sun/nio/fs/BsdFileSystemProvider.java @@ -47,37 +47,4 @@ BsdFileStore getFileStore(UnixPath path) throws IOException { return new BsdFileStore(path); } - - @Override - @SuppressWarnings("unchecked") - public <V extends FileAttributeView> V getFileAttributeView(Path obj, - Class<V> type, - LinkOption... options) - { - return super.getFileAttributeView(obj, type, options); - } - - @Override - public DynamicFileAttributeView getFileAttributeView(Path obj, - String name, - LinkOption... options) - { - return super.getFileAttributeView(obj, name, options); - } - - @Override - @SuppressWarnings("unchecked") - public <A extends BasicFileAttributes> A readAttributes(Path file, - Class<A> type, - LinkOption... options) - throws IOException - { - if (type == DosFileAttributes.class) { - DosFileAttributeView view = - getFileAttributeView(file, DosFileAttributeView.class, options); - return (A) view.readAttributes(); - } else { - return super.readAttributes(file, type, options); - } - } }
26-01-2012