Generate Key Hash for Facebook SDK android

KeyHash.java

private void getKeyHash() {
    try {
        PackageInfo info = getPackageManager().getPackageInfo(
                "your Application Id",
                PackageManager.GET_SIGNATURES);
        for (Signature signature : info.signatures) {
            MessageDigest md = MessageDigest.getInstance("SHA");
            md.update(signature.toByteArray());
            Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT));
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}