code: public Charge retrieve(String chargeId) throws BaseException {
  
  		logger.debug("Enter ChargeService::retrieve");
  		
  		if (StringUtils.isBlank(chargeId)) {
  			logger.error("IllegalArgumentException {}", chargeId);
  			throw new IllegalArgumentException("chargeId cannot be empty or null");
  		}
  
  		// prepare API url
  		String apiUrl = requestContext.getBaseUrl() + "charges/{id}".replaceAll("\\{format\\}", "json")
  				.replaceAll("\\{" + "id" + "\\}", chargeId.toString());
  		logger.info("apiUrl - " + apiUrl);
  
  		// assign TypeReference for deserialization
  		TypeReference<Charge> typeReference = new TypeReference<Charge>() {
  		};
  
  		// prepare service request
  		Request request = new Request.RequestBuilder(MethodType.GET, apiUrl).typeReference(typeReference)
  				.context(requestContext).build();
  
  		// make API call
  		Response response = sendRequest(request);
  
  		// retrieve response
  		Charge chargeResponse = (Charge) response.getResponseObject();
  
  		// set additional attributes
  		prepareResponse(request, response, chargeResponse);
  		return chargeResponse;
  	}
docs: Method to retrieve Charge
  
  @param chargeId
  @return
  @throws BaseException