core/src/in/srain/cube/diskcache/FileUtils.java
public static void deleteDirectoryQuickly(File dir) throws IOException {

        if (!dir.exists()) {
            return;
        }
        final File to = new File(dir.getAbsolutePath() + System.currentTimeMillis());
        dir.renameTo(to);
        if (!dir.exists()) {
            // rebuild
            dir.mkdirs();
        }

        // try to run "rm -r" to remove the whole directory
        if (to.exists()) {
            String deleteCmd = "rm -r " + to;
            Runtime runtime = Runtime.getRuntime();
            try {
                Process process = runtime.exec(deleteCmd);
                process.waitFor();
            } catch (IOException e) {

            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        if (!to.exists()) {
            return;
        }
        deleteDirectoryRecursively(to);
        if (to.exists()) {
            to.delete();
        }
    }
public static void deleteDirectoryQuickly(File dir) throws IOException {

        if (!dir.exists()) {
            return;
        }
        final File to = new File(dir.getAbsolutePath() + System.currentTimeMillis());
        dir.renameTo(to);
        if (!dir.exists()) {
            // rebuild
            dir.mkdirs();
        }

        // try to run "rm -r" to remove the whole directory
        if (to.exists()) {
            String deleteCmd = "rm -r " + to;
            Runtime runtime = Runtime.getRuntime();
            try {
                Process process = runtime.exec(deleteCmd);
                process.waitFor();
            } catch (IOException e) {

            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        if (!to.exists()) {
            return;
        }
        deleteDirectoryRecursively(to);
        if (to.exists()) {
            to.delete();
        }
    }
Try to delete directory in a fast way.