PostJSON in ThingWorx 9.0 Extension SDK

Has anybody been successful using the ContentLoader functions in TWx 9.0 Extension SDK?  I've been following this example and this javadoc but I keep getting a null pointer exception.  Just to test my sanity, I used the same url, header, and content information inside a Composer service and I was successful.  I've attached the stack trace and the code I'm using is:

public Boolean myService() throws Exception {
	Boolean verify = false;	
		
	ContentLoader verifyCheck = new ContentLoader(); 
		
		
	String url = "https://postman-echo.com/post";
		
 JSONObject content = new JSONObject("{\"meta\":{\"key\": \"" + "abc" + "\"}}");
 String username = null;
 String password = null;
 JSONObject headers = null;
 Boolean ignoreSSLErrors = null;
 Boolean withCookies = null;
 Double timeout = null;
 Boolean useNTLM = null;
 String workstation = null;
 String domain = null;
 Boolean useProxy = null;
 String proxyHost = null;
 Integer proxyPort = null;
 String proxyScheme = null;
 
 try { 	
 _logger.warn("URL in myService(): " + url.toString()); 
 _logger.warn("Content in myService(): " + content.toString()); 
 	 
 verifyCheck.PostJSON(url, content, username, password, headers, 
 ignoreSSLErrors, withCookies, timeout, useNTLM, workstation, domain, useProxy, 
 proxyHost, proxyPort, proxyScheme); 	
 }
 catch(Exception e)
 {
 	StringWriter sw = new StringWriter();
 	PrintWriter pw = new PrintWriter(sw);
 	e.printStackTrace(pw);
 	
 	_logger.error("Exception in myService(): " + sw.toString()); 
 }
		return verify;
	}