function export()
{
    // Get a database object.
    $db = JFactory::getDbo();

    // Create a new query object.
    $query = $db->getQuery(true);

    // Select fields to get.
    $fields = array(
        $db->quoteName('params')
    );

    // Conditions for which records should be get.
    $conditions = array(
        $db->quoteName('element') . ' = ' . $db->quote('plugin_name'),
        $db->quoteName('folder') . ' = ' . $db->quote('system')
    );

    // Set the query and load the result.
    $query->select($fields)->from($db->quoteName('#__extensions'))->where($conditions);
    $db->setQuery($query);
    $results = $db->loadResult();

    // Namming the filename that will be generated.
    $name      = 'file_name';
    $date      = date("Ymd");
    $json_name = $name."-".$date;

    // Clean the output buffer.
    ob_start();
    echo $results;
    $fileContent = ob_get_contents();
    ob_end_clean();

    header('Content-disposition: attachment; filename='.$json_name.'.json');
    header('Content-type: application/json');

    echo $fileContent;
    exit();
}

function import($_FILES)
{
    if ($_FILES['fileToUpload']['error'] > 0) {
        echo "<p class='alert alert-error'>An error occurred while uploading!</p>";
    } else {
        $file_name = $_FILES['fileToUpload']['name'];
        $file_ext  = strtolower(end(explode(".", $file_name)));
        $file_size = $_FILES['fileToUpload']['size'];
        if (($file_ext == "json") && ($file_size < 50000)) {
            $options = file_get_contents($_FILES['fileToUpload']['tmp_name']);

            // Get a database object.
            $db = JFactory::getDbo();

            // Create a new query object.
            $query = $db->getQuery(true);

            // Fields to update.
            $fields = array(
                $db->quoteName('params') . ' = ' . $db->quote($options)
            );

            // Conditions for which records should be updated.
            $conditions = array(
                $db->quoteName('element') . ' = ' . $db->quote('plugin_name'),
                $db->quoteName('folder') . ' = ' . $db->quote('system')
            );

            // Set the query and execute it.
            $query->update($db->quoteName('#__extensions'))->set($fields)->where($conditions);
            $db->setQuery($query);
            $result = $db->execute();

            echo "<p class='alert alert-success'>Backup file successfully restored!</p>";
        } else {
            if ($file_ext != "json") {
                echo "<p class='alert alert-error'>Invalid file type!";
            } elseif ($file_size > 50000) {
                echo "<p class='alert alert-error'>File size error!</p>";
            }
        }
    }
    return;
}

$jinput = JFactory::getApplication()->input;
$files  = $input->files->get('jform1');

function import($files)
{
     // rest of code here
}

Array
(
    [test] => Array
        (
            [0] => Array
                (
                    [name] => file.png
                    [type] => image/png
                    [tmp_name] => /tmp/phpXoIpSD
                    [error] => 0
                    [size] => 34409
                )

            [1] => Array
                (
                    [name] => file2.jpg
                    [type] => image/jpeg
                    [tmp_name] => /tmp/phpWDE7ye
                    [error] => 0
                    [size] => 99529
                )

        )

)

strtolower(pathinfo($filename, PATHINFO_EXTENSION))