How to lock files in a tomcat web application?

The Java manual says:

The locks held on a particular file by a single Java virtual machine do not overlap. The overlaps method may be used to test whether a candidate lock range overla开发者_StackOverflow中文版ps an existing lock.

I guess that if I lock a file in a tomcat web application I can't be sure that every call to this application is done by a different JVM, can I? So how can I lock files within my tomcat application in a reliable way?

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I was actually having the exact opposite problem -- my servlet was causing files to get locked that wouldn't clear when the context was reloaded. Of course the reason was because I was opening up InputStreams/BufferedReaders and not closing them. For you, opening up the files in this fashion might be a pretty low-tech solution to your problem as it should result in a lock at the O/S level, which is probably what you want.