GWT Designer for Eclipse 3.6 can cause project compile freeze

Lately I installed GWT Designer for Eclipse Helios (3.6). I wanted to check it's features. They aren't so cool I've expected but that's other story. The problem was that suddenly my main GWT enabled project began to freeze during compilation.  The project is maven enabled also. So it freezed in about half of compilation. All other features of Eclipse worked well. Restarting Eclipse and Windows didn't help anyway. After about an hour of investigating I've found that GWT Designer caused this. After removing it all came back to order. Ofcourse I suspect that something is wrong with my Eclipse for example I have too many bizzarre plugins installed but if I could have such problems you could have them too. So be warned :-)

(Another) GWT exception in Development Mode

Lately I got a new kind of exception during GWT Development Mode startup.

java.lang.NullPointerException
 at com.google.gwt.dev.resource.impl.DirectoryClassPathEntry.descendToFindResources(DirectoryClassPathEntry.java:79)
 at com.google.gwt.dev.resource.impl.DirectoryClassPathEntry.findApplicableResources(DirectoryClassPathEntry.java:54)
 at com.google.gwt.dev.resource.impl.ResourceOracleImpl.refresh(ResourceOracleImpl.java:351)
 at com.google.gwt.dev.cfg.ModuleDef.refresh(ModuleDef.java:386)
 at com.google.gwt.dev.cfg.ModuleDefLoader.tryGetLoadedModule(ModuleDefLoader.java:150)
 at com.google.gwt.dev.cfg.ModuleDefLoader.loadFromClassPath(ModuleDefLoader.java:136)
 at com.google.gwt.dev.DevModeBase.loadModule(DevModeBase.java:963)
 at com.google.gwt.dev.DevMode.loadModule(DevMode.java:468)
...
This was because after I started Development Mode, my IDE cleaned compiled classes directory(target/classes/ in my case). Rebuild project and I'll be back to game :) Did you like the post? Was it helpful? Leave a comment!

GWT exception in Hosted Mode

I work with GWT version 1.7.0. It's old but our product requires it. Recently I had to debug using Hosted mode under Windows XP. During Hosted mode startup I had an exception

2011-02-08 17:04:31,578 [FATAL] Uncaught Exception:
com.google.gwt.core.client.JavaScriptException:(TypeError):
Object doesn't support this property or method. number: -2146827850
 description: Obiekt nie obsługuje tej właściwości lub metody.
    at com.google.gwt.user.client.impl.DOMImplStandard.initEventSystem(Native Method)
    at com.google.gwt.user.client.impl.DOMImplMozilla.initEventSystem(DOMImplMozilla.java:39)
    at com.google.gwt.user.client.impl.DOMImpl.maybeInitializeEventSystem(DOMImpl.java:111)
    at com.google.gwt.user.client.impl.DOMImplStandard.sinkEvents(DOMImplStandard.java:140)
    at com.google.gwt.user.client.impl.DOMImplMozilla.sinkEvents(DOMImplMozilla.java:27)
    at com.google.gwt.user.client.DOM.sinkEvents(DOM.java:1221)

After some investigation I found the reason.
During development, for performance reasons I compile my GWT apps only for Firefox. So this was the case. You must know that in earlier versions of GWT (and so in 1.7.0), application is displayed in special window with embedded Internet Explorer. And now you might look closer to the stacktrace above and see that there are some Mozilla classes involved and that's wrong because for IE we should have only IE classes! So that's the cause I had exception.

So if you want to run Hosted mode you have to compile your GWT application at least with IE support. Add this to you *.gwt.xml config file

Or leave it without declaring user.agent so it would be compiled for all supported browsers. Too shame that GWT doesn't warn if it was not compiled for current browser.

If you still have problems with mentioned exception look at an issue in GWT bug tracker.