How to atomically rename a file in Java, even if the dest file already exists?

java file cross-platform
Sébastien RoccaSerra picture Sébastien RoccaSerra · Feb 27, 2009 · Viewed 34.5k times · Source

I have a cluster of machines, each running a Java app.

These Java apps need to access a unique resource.txt file concurently.

I need to atomically rename a temp.txt file to resource.txt in Java, even if resource.txt already exist.

Deleting resource.txt and renaming temp.txt doesn't work, as it's not atomic (it creates a small timeframe where resource.txt doesn't exist).

And it should be cross-platform...

Thanks !

Answer

Eirik W picture Eirik W · May 10, 2012

For Java 1.7+, use java.nio.file.Files.move(Path source, Path target, CopyOption... options) with CopyOptions "REPLACE_EXISTING" and "ATOMIC_MOVE".

See API documentation for more information.

For example:

Files.move(src, dst, StandardCopyOption.ATOMIC_MOVE);

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