I think we need some more details - for example, what is the file name (or would you prefer to specify it on the command line), what is the type of file and its contents (e.g. plain text, XML, binary, compressed archive) and what sort of changes do you need to make?
Charles Lyons (SCJP 1.4, April 2003; SCJP 5, Dec 2006; SCWCD 1.4b, April 2004)
Author of OCEJWCD Study Companion for Oracle Exam 1Z0-899 (ISBN 0955160340 / AmazonAmazon UK )
In short, you can overwrite bytes in the middle of a file, but you can't easily replace old stuff with new stuff of a different length. So change and append are easy, but insert and delete are tough. It's common to read all of the old file and write a totally new one with the same or changed content.
See RandomAccessFile if you can be sure the data length doesn't change. Otherwise just read and write with whatever IO works with your data. [ March 16, 2006: Message edited by: Stan James ]
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