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copied!<p>A better solution would be something like this:</p> <pre><code>public class Whatever { private String text; private final Object TEXT_LOCK = new Object(); public void setText(final String newText) { synchronized (TEXT_LOCK) { text = newText; } SwingUtilities.invokeLater(new Runnable() { public void run() { someLabel.setText(newText); } }); } public String getText() { synchronized (TEXT_LOCK) { return text; } } } </code></pre> <p>This will ensure that if two threads try to call <code>setText</code> concurrently then they will not clobber each other. The first thread in will set the value of <code>text</code> and enqueue a UI update with that value. The second thread will also set the value of <code>text</code> and enqueue a second UI update.</p> <p>The end result is that the UI will eventually show the most recent text value, but the internal <code>text</code> variable will <strong>immediately</strong> contain the most recent value.</p> <p>A couple of notes:</p> <ol> <li>Using a seperate lock object (i.e. <code>TEXT_LOCK</code>) means you are not vulnerable to code somewhere else locking the monitor on the <code>Whatever</code> instance and inadvertently causing a deadlock. Best to always keep tight control of your lock objects. It's also best to minimize the size of your synchronized blocks.</li> <li>You <em>could</em> make the whole <code>setText</code> method synchronized, subject to the caveat that it does make you potentially vulnerable to deadlock as above.</li> <li>Reading the value of <code>text</code> also needs to be synchronized even though <code>Strings</code> are immutable. There are subtleties to the Java memory model that mean you <em>always</em> need to synchronize around variables that can be read/written by multiple threads.</li> </ol> <p>Check out Brian Goetz's <a href="http://rads.stackoverflow.com/amzn/click/0321349601" rel="noreferrer">Java Concurrency in Practice</a> for a great dive into the tricky parts of concurrency (including the memory model weirdness).</p>

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