Cannot access database from addon

Dear All,

I face a problem with establishing a connection to MySQL from add-on,
im accessing the database as follows:

In the addon there is a button so when i press it, a javascript
function is called.
after that using a XPCOM component to get the object of a java class,
i use this object to call a java function, this function is
responsible to establish a connection to a MySQL database, but this
java function cannot establish a connection.

My XPCOM component is work well, so the problem not in my component.

I test the java code using netBeans and the connection is established,
but using the addon the connection was not established.

Does mozilla permit to access a database from addon or not??

Is there any configuration in the security policy?

Thanks