Decodes JWT from Base64 to a StringArray

JWTDecoder.java

static byte[] decodeBase64(String encoded) {
   return Base64.getDecoder().decode(encoded);
}

static String[] decodeJwt(String encodedIdToken) {
        String[] splitIdToken = encodedIdToken.split("\\.");
        String header = new String(decodeBase64(splitIdToken[0]));
        String payload = new String(decodeBase64(splitIdToken[1]));
        String signature = splitIdToken[2];  // decode this for later, kept on having decode errors
        return {header, payload, signature};
    }