Calculate HMAC SHA-256 for a given message

HmacCalculator.java

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

public String calculateSignature() {
	String secretKey = "<insert secret key here>";
	String serialized = "order_id=1464092311945&status=CHARGED&status_id=21";
	String algorithm = "HmacSHA256";
	serialized = URLEncoder.encode(serialized);

	SecretKeySpec secretKeySpec = new SecretKeySpec(secretKey.getBytes(), algorithm);
	Mac mac = Mac.getInstance(algorithm);
	mac.init(secretKeySpec);
	byte[] digest = mac.doFinal(serialized.getBytes());
	return URLEncoder.encode(digest.encodeBase64().toString());
}

calculateSignature();