### Question:
ParameterAccessor { public static <T> T getParameterValue(String name, Class<T> valueClass, ContentDeliveryConfig config) { Parameter<T> param = getParameter(name, valueClass, config); if(param != null) { return param.getValue(); } return null; }  static T getParameterValue(String name, Class<T> valueClass, ContentDeliveryConfig config); static T getParameterValue(String name,  Class<T> valueClass, T defaultVal, ContentDeliveryConfig config); static Parameter<T> getParameter(String name, Class<T> valueType, ContentDeliveryConfig config); static Parameter<T> getParameter(String name, Class<T> valueType, Map<String, List<SmooksResourceConfiguration>> resourceConfigurations); static T getParameterValue(String name, Class<T> valueType, T defaultVal, Map<String, List<SmooksResourceConfiguration>> config); static T getParameterValue(String name, Class<T> valueType, Map<String, List<SmooksResourceConfiguration>> resourceConfigurations); static void setParameter(String name, Object value, Smooks smooks); static void removeParameter(String name, Smooks smooks); static final String GLOBAL_PARAMETERS; }### Answer:
@Test public void test_system_property() { Smooks smooks = new Smooks(); ContentDeliveryConfig deliveryConfig = smooks.createExecutionContext().getDeliveryConfig(); assertNull(ParameterAccessor.getParameterValue("test.parameter", String.class, deliveryConfig)); System.setProperty("test.parameter", "xxxxxxx"); assertEquals("xxxxxxx", ParameterAccessor.getParameterValue("test.parameter", String.class, deliveryConfig)); }