Mysterious EOF exception while reading a file with Java IO functions

Question

Hi, I got following exception when I am trying to seek to some file.

> Error while seeking to 38128 in myFile, File length: 85742 java.io.EOFException at java.io.RandomAccessFile.readInt(RandomAccessFile.java:725) at java.io.RandomAccessFile.readLong(RandomAccessFile.java:758) >

But If you see I am trying to seek to '38128' where as file length is '85742'. It reported EOF exception. I wonder how it is possible? Another process appends contents to that file periodically and closes the file handler. It appends contents using DataOutputStream. My process is trying to seek to some locations and reading it. One more thing is I got this exception only once. I tried to reproduce it but it never happened again. The file is in local disk only. No filer.

Thanks D. L. Kumar

Answer 1

I would be very careful when trying to do random access on a file that is concurrently being written to from another process. It might lead to all kinds of strange synchronisation problems, as you are experiencing right now.

Do you determine the length of the file from the same process as the one doing the seek()? Has the other modifying processing done a flush()?

Answer 2

The process writing the data may have been told to write the data, but the data could be buffered to write. Be sure to call flush() on the output stream prior to attempting to read the data.