Unserialize WP_Options options programatically?

The get_option and update_option functions in PHP automatically handle serialization/unserialization for you:

https://codex.wordpress.org/Function_Reference/get_option

If you need to interface with these functions using JavaScript (assuming JavaScript and not Java, as others have pointed out) you could register an AJAX endpoint that calls these functions for you that you can interface with via JavaScript on the front-end:

https://codex.wordpress.org/AJAX_in_Plugins