401 - using peek and lock Rest API

I am referring to following link : https://msdn.microsoft.com/en-us/library/azure/hh780722.aspx

I am currently using java with jersey client to using this API but receiving 401. The response entity is empty and i dont know specifically what is wrong.I have tried regenerating the Primary_key from the portal but still see the same issue.

Here is the code snippet

private static final String ENDPOINT = "datamstorequeue/messages/head";
	private static final String HOST = "https://<namespace>.servicebus.windows.net/";

	@Override
	public String getMessage() {
		final ClientConfig readClientConfig = new DefaultClientConfig();
		readClientConfig.getFeatures().put(JSONConfiguration.FEATURE_POJO_MAPPING,
				Boolean.TRUE);
		Client readClient =  Client.create(readClientConfig);
		WebResource webResource = readClient.resource(HOST + ENDPOINT);
		String key = GetSASToken(HOST + ENDPOINT,"All",Constants.QUEUE_PRIMARY_KEY);
		System.out.println("key:"+ key);
		ClientResponse response = webResource.header("Authorization", key)
                                          .header("Content-Length", 0).post(ClientResponse.class);


		if (response.getStatus() != 200) {
			String output = response.getEntity(String.class);
			System.out.println("Failed : HTTP error code : "+ response.getStatus() + output);
		}

		String output = response.getEntity(String.class);
		System.out.println("Output : " + output);

		return output;
	}


    private static String GetSASToken(String resourceUri, String keyName, String key)
    {
    	long epoch = System.currentTimeMillis()/1000L + 60 ;
    	String expiry = Long.toString(epoch);

    	String sasToken = null;
try {
			String stringToSign = URLEncoder.encode(resourceUri, "UTF-8") + "\n" + expiry;

			String signature = getHMAC256(key, stringToSign);
			//SharedAccessSignature sig=<signature-string>&se=<expiry>&skn=<keyName>&sr=<URL-encoded-resourceURI>

 			sasToken = "SharedAccessSignature sr=" + URLEncoder.encode(resourceUri, "UTF-8") +"&sig=" +
					URLEncoder.encode(signature, "UTF-8") + "&se=" + expiry + "&skn=All";
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

        return sasToken;
    }


	public static String getHMAC256(String key, String input) {
		byte[] base64key = Base64.decodeBase64(key.getBytes());
		Mac sha256_HMAC = null;
		String hash = null;
		try {
			sha256_HMAC = Mac.getInstance("HmacSHA256");
			SecretKeySpec secret_key = new SecretKeySpec(base64key, "HmacSHA256");
			sha256_HMAC.init(secret_key);
			hash = new String(Base64.encodeBase64(sha256_HMAC.doFinal(input.getBytes("UTF-8"))));
		} catch (InvalidKeyException e) {
			e.printStackTrace();
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		} catch (IllegalStateException e) {
			e.printStackTrace();
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}

		return hash;
	} 

I am not sure what can i improve in above code to correct my SAS key.

It looks something like this :

SharedAccessSignature sr=https%3A%2F%2F<namespace>.servicebus.windows.net%2Fdatamstorequeue%2Fmessages%2Fhead&sig=AHyMSNl9tmURr7l0gHzt4rOlS1jjTx9Hi4h13UzcMl4%3D&se=1437443740&skn=All