This is what we use to access the property value from the return value of issuePropertyService.getProperty:
public static <T> T getEntityPropertyOrNull(PropertyResult propertyResult) {
try {
Object option = propertyResult.getClass().getMethod("getEntityProperty").invoke(propertyResult);
return option.getClass().getMethod("getOrNull").invoke(option);
} catch (InvocationTargetException | NoSuchMethodException | IllegalAccessException var2) {
throw new IllegalStateException(var2);
}
}