1.What is GWT?
Google Web Toolkit (GWT) is a development toolkit for building and optimizing complex browser-based applications. GWT is used by many products at Google, including Google AdWords and Orkut.
2.What are the features of GWT?
Following are the features of GWT −
Google Web Toolkit (GWT) is a development toolkit to create RICH Internet Application(RIA).
GWT provides developers option to write client side application in JAVA.
GWT compiles the code written in JAVA to JavaScript code.
Application written in GWT is cross-browser compliant. GWT automatically generates javascript code suitable for each browser.
GWT is open source, completely free, and used by thousands of developers around the world. It is licensed under the Apache License version 2.0.
3.What are the core components of GWT?
Following are the core components of GWT −
GWT Java to JavaScript compiler − This is the most important part of GWT which makes it a powerful tool for building RIAs. The GWT compiler is used to translate all the application code written in Java into JavaScript.
JRE Emulation library − Google Web Toolkit includes a library that emulates a subset of the Java runtime library. The list includes java.lang, java.lang.annotation, java.math, java.io, java.sql, java.util and java.util.logging.
GWT UI building library − This part of GWT consists of many subparts which includes the actual UI components, RPC support, History management, and much more.
GWT Hosted Web Browser − GWT Hosted Web Browser lets you run and execute your GWT applications in hosted mode, where your code runs as Java in the Java Virtual Machine without compiling to JavaScript.
4.What is Module descriptor in GWT?
A module descriptor is the configuration file in the form of XML which is used to configure a GWT application. A module descriptor file extension is *.gwt.xml, where * is the name of the application and this file should reside in the project’s root.
5.What is the purpose of ‘module’ tag in *.gwt.xml file in GWT?
This provides name of the application.
6.What is the purpose of ‘inherits’ tag in *.gwt.xml file in GWT?
This adds other gwt module in application just like import does in java applications. Any number of modules can be inherited in this manner.
7.What is the purpose of ‘entry-point’ tag in *.gwt.xml file in GWT?
This specifies the name of class which will start loading the GWT Application.
8.Can you have multiple entry-point classes in a *.gwt.xml file?
Yes! Any number of entry-point classes can be added.
9.Which method of a entry-point class is called when GWT application starts?
onModuleLoad() function gets called and acts similar to main method of a java application.
10.How onModuleLoad() functions get called if multiple entry-point classes are specified in *.gwt.xml?
They are called sequentially in the order in which entry-point classes appear in the module file. So when the onModuleLoad() of your first entry point finishes, the next entry point is called immediately.