Getting Exception in thread "main" java.lang.VerifyError: class com.google.gwt.dev.HostedModeBase$ArgHandlerNoServerFlag

Question

I am trying to upgrade my application from GWT 2.0 to 2.7.0 and getting below exception. I am using the below mentioned jars. What is the reason for this exception ? Is there any migration guide or document that i can refer for upgrading to 2.7 gwt version ?

Exception in thread "main" java.lang.VerifyError: class com.google.gwt.dev.HostedModeBase$ArgHandlerNoServerFlag overrides final method getPurpose.()Ljava/lang/String;
at java.lang.ClassLoader.defineClass1(Native Method)

Jars used :

gwt-user-2.7.0.jar

get-dev-2.7.0.jar

gwt-servlet-2.7.0.jar

gwt-dev-windows.jar

gwtext.jar

Answer 1

gwt-dev-windows.jar is an old dependency from pre-2.0 GWT (you should have already removed it when updating to 2.0 a while ago), and it conflicts here with the newer gwt-dev-2.7.0.jar.

BTW, unless you want to continue using "classic DevMode", you'll also need gwt-codeserver-2.7.0.jar.

Last, but not least, you'll likely have to update your GWT-Ext dependency as well.