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

[Sean Chou]

Oh, I should have done a little more investigation.

Is there a plan to fix it? I can provide a patch if it is needed.

2011/2/17 Alan Bateman <Alan.Bateman at oracle.com>

> 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.
>



-- 
Best Regards,
Sean Chou