Mendix uses the dojo framework but jquery is used as well in some widgets (see calender widget for example).
After a some googling I get the impression that is harder to combine GWT with dojo than jquery. But I have no experience with it.
Usually I use jquery when a nice widget is offered, what are you looking for?
Edit: if you want to create module that allows you to receive and send mail via google use the java libaries that Google provides.
I want to create a module that implements gmail api.
I don't think you should use GWT to solve your mail server connectivity problem. Since GWT is meant to be a client side library it would collide with or overwrite large parts of mendix/dojo. It might be possible to let both libraries work together but this would create a very fat client of which i am not sure you would want that either.
I would suggest to use some form of server side integration that will allow you to sync the server with gmail and then show that data on your forms. Then again maby you could somehow realise an integration with gwt that reads directly from your gmail and does not store the mail except for a selected few. This could possibly reduce your amount of disk space :]
It all depends on what type of solution you are looking for and how much of the mendix/dojo framework you want to reuse.
I don't think you should use GWT to solve your mail server connectivity problem. Since GWT is meant to be a client side library it would collide with or overwrite large parts of mendix/dojo. It might be possible to let both libraries work together but this would create a very fat client of which i am not sure you would want that either.
I would suggest to use some form of server side integration that will allow you to sync the server with gmail and then show that data on your forms. Then again maby you could somehow realise an integration with gwt that reads directly from your gmail and does not store the mail except for a selected few. This could possibly reduce your amount of disk space :]
It all depends on what type of solution you are looking for and how much of the mendix/dojo framework you want to reuse.