java - select element list under textbox -

in web page there field name street name:* , when put in number , list of addresses ,which have number, appears under field.
when click on 1 of addresses ,this field contains address, , other fields city or postal code automatically populated values present in street name.
want same java using junit libraries of selenium. want junit clicks on 1 of elements of list appears under field street name:* after having inserted number in field.

private webdriver driver= new firefoxdriver(); webelement street_name=driver.findelement(by.id("street_name"));  string pac_input="3";  street_name.sendkeys(pac_input); 

i insert webelement, street_name value "3" , under box appears list of addresses have number "3" want junit clicks on 1 of elements of list java command should use filling webelement value selected in list appears under box street_name ?

how can it? help, alberto