security - How to securely delete files in java

Question

How do I securely delete files in java? I tried the code at javafaq.nu, but the problem is you can't actually delete the file on windows once it has been mapped due to this bug.

Then I tried just using sysinternals sdelete on windows, but you have to click a usage agreement the first time you use it which I want to avoid.

Answer 1

I coded and tried this function, and it seemed to work:

public static void secureDelete(File file) throws IOException {
    if (file.exists()) {
        long length = file.length();
        SecureRandom random = new SecureRandom();
        RandomAccessFile raf = new RandomAccessFile(file, "rws");
        raf.seek(0);
        raf.getFilePointer();
        byte[] data = new byte[64];
        int pos = 0;
        while (pos < length) {
            random.nextBytes(data);
            raf.write(data);
            pos += data.length;
        }
        raf.close();
        file.delete();
    }
}