Is this object cached?

I have some data of an object,generated by a class, saved as post meta.
This is the class:

Class OBJ{
function get_data(){
$meta_data = get_post_custom($id);
$this->stuffs_1 = $meta_data[stuffs_1];
$this->stuffs_2 = $meta_data[stuffs_2]; 

function save_data(){

if this , then, that ....
....
add_post_meta(....);
....
update_post_meta(...);
}
}

In the template:
$obj = new OBJ($id);
Then, lots of functions are using $obj->stuffs.

I understand WP’s post meta are cached. But, is this $obj cached?
if $obj is not cached, what else I should do?