title: How do I speed up the gwt compiler?
body: <p>We're starting to make heavier use of GWT in our projects, and the performance of the GWT compiler is becoming increasingly annoying. </p>
  
  <p>We're going to start altering our working practices to mitigate the problem, including a greater emphasis on the hosted-mode browser, which defers the need to run the GWT compiler until a later time, but that brings its own risks, particularly that of not catching issues with real browsers until much later than we'd like.</p>
  
  <p>Ideally, we'd like to make the GWT compiler itself quicker - a minute to compile a fairly small application is taking the piss. However, we are using the compile if a fairly naive fashion, so I'm hoping we can make some quick and easy gains.</p>
  
  <p>We're currently invoking com.google.gwt.dev.Compiler as a java application from ant Ant target, with 256m max heap and lots of stack space. The compiler is launched by Ant using fork=true and the latest Java 6 JRE, to try and take advantage of Java6's improved performance. We pass our main controller class to the compiler along with the application classpath, and off it goes.</p>
  
  <p>What else can we do to get some extra speed? Can we give it more information so it spends less time doing discovery of what to do?</p>
  
  <p>I know we can tell it to only compile for one browser, but we need to do multi-browser testing, so that's not really practical.</p>
  
  <p>All suggestions welcome at this point.</p>