You can't index elements using []
in CSS selectors.
Here is what you might want to try:
@FindBy(how=How.CSS,using = "li.ui-menu-item:nth-of-type(2) > a[id^='ui-id-']")
Or use XPath
@FindBy(how=How.XPATH,using = "(//a[starts-with(@id, 'ui-id-')])[2]")