Review

Uses static key.

• missing/condition/value_or_state

SaavnFileRunner.java

decryptPlay(String)

class SaavnFileRunner {
    private String decryptPlay(final String str) throws Exception {
        final Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(SECRET_KEY, "DES"));
        return new String(cipher.doFinal(Base64.decodeBase64(str)), "UTF-8");
    }

}