FULL PRODUCT VERSION :
java version "1.6.0_18"
Java(TM) SE Runtime Environment (build 1.6.0_18-b07)
Java HotSpot(TM) Server VM (build 16.0-b13, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Linux Darksun 2.6.32.3 #4 SMP Mon Jan 11 20:07:48 CET 2010 i686 Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz GenuineIntel GNU/Linux

32bit Crux Linux 2.6

EXTRA RELEVANT SYSTEM CONFIGURATION :
With an OpenSolaris 06/09 Virtual Machine the expected result is achieved.
Open Solaris java version:

java version "1.6.0_13"
Java(TM) SE Runtime Environment (build 1.6.0_13-b03)
Java HotSpot(TM) Client VM (build 11.3-b02, mixed mode)


A DESCRIPTION OF THE PROBLEM :
The bytes in the second write call are appended to the file and not inserted at the specified position.



STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the code below and inspect the resulting file in a hex editor.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
A file containing the bytes "01 05 06 04".
ACTUAL -
A file containing the bytes "01 02 03 04 05 06".

ERROR MESSAGES/STACK TRACES THAT OCCUR :
None


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
package filechanneltest;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

/**
 *
 * @author markus
 */
public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws IOException
    {
        File tmpFile = File.createTempFile("test", ".bin");

        FileChannel writer = new FileOutputStream(tmpFile).getChannel();

        byte[] bytes = {1, 2, 3, 4};
        ByteBuffer bb = ByteBuffer.wrap(bytes);

        writer.write(bb);
        writer.close();

        byte [] newBytes = {5,6};
        bb = ByteBuffer.wrap(newBytes);

        writer = new FileOutputStream(tmpFile, true).getChannel();
        writer.write(bb, 1);

        writer.close();

        System.out.println(tmpFile.getAbsolutePath());
        System.exit(0);
    }

}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
package filechanneltest;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;

/**
 *
 * @author markus
 */
public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws IOException
    {
        File tmpFile = File.createTempFile("test", ".bin");

        FileChannel writer = new FileOutputStream(tmpFile).getChannel();

        byte[] bytes = {1, 2, 3, 4};
        ByteBuffer bb = ByteBuffer.wrap(bytes);

        writer.write(bb);
        writer.close();

        byte [] newBytes = {5,6};
        bb = ByteBuffer.wrap(newBytes);

// writer = new FileOutputStream(tmpFile, true).getChannel();
        writer = new RandomAccessFile(tmpFile, "rw").getChannel();
        writer.write(bb, 1);

        writer.close();

        System.out.println(tmpFile.getAbsolutePath());
        System.exit(0);
    }

}