Question

I have this GWT code below which have some slight problem:

It’s either the login and aboutme property is set or just the contacts is set which ever comes first in the line. Could this be that the contacts property is set before the for-loop is finished, resulting in contacts being assigned a null?

public void copyFrom(User user) {
        Map<String,String> map = new HashMap<String,String>();
        for (Contact contact : user.getContacts()) {
            map.put(contact.getType(), contact.getValue());
        }
        super.set("lastlogin", user.getLastLogin());
        super.set("aboutme", user.getAboutMe());
        super.set("contacts", map);
    }

Do I need to use a “faster” Map?

Answer 1

Neither a for loop, nor adding values to a Map are asynchronous operations, so that entire loop executes prior to the calls to super.set(...). The map, in this case, cannot be null, since you instantiate it at the moment of declaration. It could end up being unpopulated (for instance, if there were no elements in user.getContacts()), but not null.

Your problem lies in the implementation of set(...) by whatever super is in this case.