Does Swing component initialization have to occur on the EDT?

[Ken Blair]

For example:

JTextField field = new JTextField(10);

Must the initialization of a Swing component occur on the EDT or may the initialization occur on any thread? Obviously altering the components later needs to be on the EDT, showing a JFrame for example or changing the Border of a JComponent. I would have expected the initialization to be safe, but now that I encounter even more lunacy in Swing I'm not so sure. If this must occur on the EDT, how do you achieve it? I find invokeLater() unacceptable as it means the current thread can return with a reference to our created class where the members of that class have not necessarily been initialized, so I'd have to do something like this:

final Runnable init = new Runnable() {
    public void run() {
        field = new JTextField(10);
    }
};
if (SwingUtilities.isEventDispatchThread()) {
    init.run();
} else {
    SwingUtilities.invokeAndWait(init);
}

That would force me to make field non-final unnecessarily. The only option that would leave me with is throwing an exception if it was created outside the EDT, which may cause a lot of unnecessary headache for clients that wish to create it and constantly have to shift the creation to the EDT.

Please tell me the initialization is thread-safe at least.