Changing the current working directory in Java?

Question

How can I change the current working directory from within a Java program? Everything I\'ve been able to find about the issue claims that you simply can\'t do it, but I can\

Answer 1

There is no reliable way to do this in pure Java. Setting the user.dir property via System.setProperty() or java -Duser.dir=... does seem to affect subsequent creations of Files, but not e.g. FileOutputStreams.

The File(String parent, String child) constructor can help if you build up your directory path separately from your file path, allowing easier swapping.

An alternative is to set up a script to run Java from a different directory, or use JNI native code as suggested below.

The relevant Sun bug was closed in 2008 as "will not fix".