无法删除目录，Java

Question

In my jUnit , i have a following snippet:

private String  session = "/tmp/session/";
private File    f;

@Before
public void setUp() {
    f = new File(session);
    f.mkdir();
}

@After
public void tearDown() {
    System.out.println("Directory deleted:   " + f.delete()); // always false
}

Meanwhile:

• Directory permissions are ok ( drwxr-xr-x )
• Directory contains some files ( -rw-r--r-- )
• No ownership issues (Creator user deletes)

What would cause for f.delete() to fail? Is f.delete() an equivalent of rm -rf ?

Answer 1

The simplest way to recursively delete a non-empty directory (and not reinvent the wheel in the process) is to use functionality from an existing library, say the FileUtils.deleteQuietly() method of Apache Commons' file utils which specifies that:

If file is a directory, delete it and all sub-directories (...) A directory to be deleted does not have to be empty

Answer 2

From the API documentation for File.delete:

 delete public boolean delete() Deletes the file or directory denoted by this abstract pathname. If this pathname denotes a directory, then the directory must be empty in order to be deleted. Returns: true if and only if the file or directory is successfully deleted; false otherwise Throws: SecurityException - If a security manager exists and its SecurityManager.checkDelete(java.lang.String) method denies delete 

access to the file

Note the bit about the directory needing to be empty.

Answer 3

As said before, your directory needs to be empty before you delete it. There is a great tutorial here that you should take a look at. You need to a recursive delete of the directory and all of its files, because the directory needs to be empty before you delete it.