How to get absolute path of directory of a file?

How can I get an absolute path of a directory containing a file specified:

// cu开发者_StackOverflow社区rrent dir is "/home/me/dev"
File file = new File("./target/test.txt");
assert absolute(file).equals("/home/me/dev/target");

It's Java 6.

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You mean the methods in the documentation?

File file = new File("./target/test.txt");
String dirPath = file.getAbsoluteFile().getParentFile().getAbsolutePath()
assert dirPath.equals("/home/me/dev/target");

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assert file.getParentFile().getAbsolutePath().equals("/home/me/dev/target");