What is "gwt"

Google Web Toolkit is an open source web framework for creating applications with Ajax technology in Java programming language.

Except for some native libraries, part of the Java source code is converted to Javascript so that it can run natively in the user’s browser, i.e., on client.

GWT uses a type of RPC communication between the part that runs on the server (Java) and the part converted to Javascript that runs on the client.

Source: Wikipedia