Behavior of java.io.FileOutputStream.getChannel() does not match the spec

[Alan Bateman]

Sean Chou wrote:
> Hi,
>    I find there is a mismatch between the spec and the behavior of
> java.io.FileOutputStream.getChannel().
>
>    The spec reads: "The initial position of the returned channel will be
> equal to the number of bytes written to the file so far unless this
> stream is in append mode, in which case it will be equal to the size
> of the file. "
>
>    But we'll get size 0 in such situation. Here is the testcase:
>
> //Testcase
> import java.io.*;
>
> public class  FileOutputStreamTest{
>    public static void main(String args[]) throws Exception{
>         File tmpfile = File.createTempFile("FileOutputStream", "tmp");
>         tmpfile.deleteOnExit();
>         FileOutputStream fos = new FileOutputStream(tmpfile, false);
>         fos.write(new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 });
>         fos.close();
>
>         fos = new FileOutputStream(tmpfile, true);
>         long size = fos.getChannel().position();
>         if (10 != size){
>                // This return value is 0, mismatching the spec
>                System.out.println("Position Error Detected: except 10, 
> but was " + size);
>         }
>         fos.close();
>    }
> }
> // End of the testcase
>
>     Any comments?
>
This is a long standing issue, 6526860 but hasn't been high priority as 
it probably isn't too common to query or change the file position when 
opened for append.

-Alan.