#5: File systems look like Unix

• The file separator may not be /

• The current directory may not be where you expect.

• Absolute paths may not begin with a file separator.

• . may not refer to the current directory.

• .. may not refer to the parent of the current directory

• / may not be the root of the file system.

• Copying and moving files often involves more than reading the data in the old location and writing it in the new location.

• /tmp and /usr/tmp may not be real files

• /dev/null may be a real file

Fixes

The file separator may not be /

Use File.pathSeparator

The current directory may not be where you expect.

Ask the user to locate the file with a file dialog.

Absolute paths may not begin with a file separator.

Use the getCanonicalPath() method in the File class

. may not refer to the current directory.

use the System.getProperty("user.dir") method

.. may not refer to the parent of the current directory

use the getParent() method in the File class

/ may not be the root of the file system.

Use File.listRoots() instead (Java 1.2)

Copying and moving files often involves more than reading the data in the old location and writing it in the new location.

No good solution in pure Java. You really have to use native code.

/tmp and /usr/tmp may not be real files

Use File.createTempFile() instead (Java 1.2)

/dev/null may be a real file

Use a java.io.ByteArrayOutputStream or, better yet, a com.macfaq.io.NullOutputStream