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FileChannel.tryLock : IOException: Invalid argument

Posted on 2009-04-08
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Last Modified: 2012-05-06
I've run into a baffling problem porting a Java program over to a FreeBSD system from Trustix.  When I try to obtain a file lock on a RandomAccessFile I get an "Invalid Argument" exception.

When searching for a fix I found reference to 64-bit systems having problems with this, but that has been fixed in java 1.4.3 (IIRC).  I did try passing in a block size to tryLock() (ie: tryLock(0L, 1024L, false) ) but that did not change the result.

See code snippet for code and exception.

System:
FreeBSD 7.1, 64bit
Filesystem: UFS
java: jdk 1.6.0

Anyone have any input on this?
// code

      FileChannel channel = new RandomAccessFile("fileLockTest","rw").getChannel();

      FileLock lock = channel.tryLock();
 

// exception

java.io.IOException: Invalid argument

        at sun.nio.ch.FileChannelImpl.lock0(Native Method)

        at sun.nio.ch.FileChannelImpl.tryLock(FileChannelImpl.java:924)

        at java.nio.channels.FileChannel.tryLock(FileChannel.java:978)

        at FileLockTest.obtainRefreshLock(FileLockTest.java:47)

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Question by:malklavious
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Expert Comment

by:objects
ID: 24102518
first create the lock

      FileChannel channel = new RandomAccessFile("fileLockTest","rw").getChannel();
        FileLock lock = channel.lock();
      lock = channel.tryLock();

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Author Comment

by:malklavious
ID: 24102892
I was doing that at first, moved to the tryLock as I was trying to figure out a way to get it to work.

Tried it again, still getting the exception, now on the "channel.lock()" line.
// code

      FileChannel channel = new RandomAccessFile("fileLockTest","rws").getChannel();  

      FileLock lock = channel.lock();  // <-- exception thrown here
 

// exception

java.io.IOException: Invalid argument

        at sun.nio.ch.FileChannelImpl.lock0(Native Method)

        at sun.nio.ch.FileChannelImpl.lock(FileChannelImpl.java:887)

        at java.nio.channels.FileChannel.lock(FileChannel.java:876)

        at FileLockTest.obtainRefreshLock(FileLockTest.java:66)

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Expert Comment

by:objects
ID: 24103569
> I did try passing in a block size to tryLock() (ie: tryLock(0L, 1024L, false)

that should have worked according to:

http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6371627
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Author Comment

by:malklavious
ID: 24108006
That's exactly why I'm so baffled!  I read that bug and a couple of other bugs related to using Long.MAX_VALUE on 64-bit systems could cause problems.

I just ran a couple more tests, using start/end pairs of:

0, 1024
1, 1024
0, 0

All with the same result as above...
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Author Comment

by:malklavious
ID: 24117318
One side note, looks like the system has OpenJDK 1.6.0, so it may be an OpenJDK issue.  I'm going to try and do a test on the same OS/Filesystem with regular Java to see what happens.
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Expert Comment

by:nj_glenn
ID: 24117479
Try to run java -version from the command line.  If it doesn't report correctly, you may have a configuration error.  

Expected output:

[/usr/local/etc]$ java -version
openjdk version "1.6.0-internal"
OpenJDK Runtime Environment (build 1.6.0-internal-root_17_mar_2009_11_47-b00)
OpenJDK 64-Bit Server VM (build 11.0-b17, mixed mode)
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Author Comment

by:malklavious
ID: 24117522
Doing some more testing with different systems found that it is not isolated to OpenJDK, on a different system that is also running OpenJDK I was able to get the FileLock to work.  Seems like it is a configuration issue on the system I was doing my initial tests on.  Having my SysAdmins take a look to see what's different (they should be identical).
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Accepted Solution

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nj_glenn earned 500 total points
ID: 24117555
Interesting. Have your sys-admins be sure both versions of the JDK are the same on each machine.
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Author Comment

by:malklavious
ID: 24117619
Bingo, looks like that is the problem.  The OpenJDK versions are different.
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