code: public static String getJsonOutput(FormChecker fc) {
  		StringBuilder json = new StringBuilder();
  		String status = fc.isValidAndNotFirstRun() ? "success" : "fail";
  		json.append("{\"status\": \"" + status + "\",");
  		json.append("\"data\":");
  	
  		// Problems:
  		if (fc.isValidAndNotFirstRun()) {
  			json.append("\"null\",");
  		} else {
  			// append errors:
  			json.append("{");
  			String commaAppend = "";
  			for (FormCheckerElement elem : fc.getForm().getElements()) {
  				if (!elem.isValid()) {
  					json.append(commaAppend);
  					json.append("\"" + elem.getName() + "\":" + "\"" + elem.getValidationResult().getMessage() + "\"");
  					commaAppend = ",";
  				}
  			}
  			json.append("},");
  		}
  	
  		// no problems
  		json.append("\"okdata\":");
  		// append errors:
  		json.append("{");
  		String commaAppend = "";
  		for (FormCheckerElement elem : fc.getForm().getElements()) {
  			if (elem.isValid()) {
  				json.append(commaAppend);
  				json.append("\"" + elem.getName() + "\":" + "\"" + "OK" + "\"");
  				commaAppend = ",";
  			}
  		}
  		json.append("}");
  	
  		json.append("}");
  	
  		return json.toString();
  	}
docs: returns json output in this format: http://labs.omniti.com/labs/jsend
  
  { "status" : "fail", "data" : { "title" : "A title is required" } }
  
  
  { status : "success", data : null }
  
  @param fc
  @return