not able to delete the directory through Java

In my application I have written the code to delete the directory from drive but when I inspect the delete function of File it doesn't delete the file. I have written some thing like this

//Code to delete the directory if it exists
File directory = new File("c:\\Report\\");
if(directory.exists())
    directory.delete(); 

The directory is not in use: still it is not able to delete the directory.

in Java, directory deletion is possible only for empty directory, which leads to methods like the following :

/**
 * Force deletion of directory
 * @param path
 * @return
 */
static public boolean deleteDirectory(File path) {
    if (path.exists()) {
        File[] files = path.listFiles();
        for (int i = 0; i < files.length; i++) {
            if (files[i].isDirectory()) {
                deleteDirectory(files[i]);
            } else {
                files[i].delete();
            }
        }
    }
    return (path.delete());
}

This one will delete your folder, even if non-empty, without troubles (excepted when this directory is locked by OS).