presto-main/src/main/java/io/prestosql/operator/annotations/FunctionsParserHelper.java/FunctionsParserHelper/findConstructor
class FunctionsParserHelper:    public static Optional<Constructor<?>> findConstructor(Class<?> clazz)
    {
        Constructor<?>[] constructors = clazz.getConstructors();
        checkArgument(constructors.length <= 1, "Class [%s] must have no more than 1 public constructor", clazz.getName());
        if (constructors.length == 0) {
            return Optional.empty();
        }
        return Optional.of(constructors[0]);
    }