How mulitselect work in Java

Hello,Please tell me the function of the code below:
[code]$cross = new CrossOptionsConnector($res);
$cross->link->render_table(“event_user”,“event_id”, “user_id,event_id”);

$scheduler = new SchedulerConnector($res);
$scheduler->set_options("user_id", $cross->options);


Is it return xml?
what is it format?
I want to work in java platform

Currently this code exists only in php connectors, there is no similar helper for the java
This code allows to use many-to-many link between events and some other entities.

Is it return xml?
what is it format?

For data loading it works the same as any other custom field, just instead of command separated value will provide a comma separated list

<event id="123"> <user_id>23,45,56</user_id>

I see.
but why I can not find the DELETE statement of the sql’s query from the sample demo?

PHP connector handle it automatically ( it creates INSERT | DELETE queries for cross-link table automatically, when saving main event record )

In case of java, you can use onBeforeProcessing behavior, and execute necessary command from it , by custom code.