Question

I have a serious doubt on using GWT. GWT claims that the client codes are compiled to JavaScript and HTML, but after compiling the code, I’m still seeing .class files for the client code in my Project. Of course i do have some js and html files in WEB-INF directory, but if the java client code is completely compiled to js and html, why would there be .class files in the project?

Answer 1

This is very straightforward, if you know what is GWT. According to the Wikipedia:

GWT applications can be run in two modes:

• Development mode (formerly Hosted mode): The application is run as Java bytecode within the Java Virtual Machine (JVM). This mode
  is typically used for development, supporting hot swapping of code
  and debugging.
• Production mode (formerly Web mode): The application is run as pure JavaScript and HTML, compiled from the Java source. This mode
  is typically used for deployment.

I think you understand why you are seeing Java bytecode files(.class) are in your project. For checking it: start your project and open the web page which is generated by gwt, delete .class file(s) from client package, and it won’t work. But in production mode it works properly since it doesn’t depend on some .class files. For example, the classes which are responsible for constructing the UI.