GWT - Google Web Toolkit

👉 Overview

👀 What ?

Google Web Toolkit (GWT) is a development toolkit for building and optimizing complex browser-based applications. It is an open-source set of tools that allows developers to create and maintain complex JavaScript front-end applications in Java. GWT is used by many products at Google, including Google AdWords and Google Wallet.

🧐 Why ?

GWT is important as it enables productive development and powerful performance for Java software development teams. It allows developers to create complex web-based applications without being experts in front-end technologies like JavaScript optimization and responsive design. It also provides Java-to-JavaScript compiler and a special web browser that helps to debug the JavaScript code. By using GWT, developers can focus on building the application and the toolkit takes care of the complexity of creating efficient, cross-browser JavaScript code.

⛏️ How ?

To use GWT, you need to have a basic understanding of Java programming language. GWT provides a set of annotations and Java APIs which developers can use to write client-side applications. It also provides a special web browser, called GWT Development Mode, where developers can debug their GWT applications just like any other Java application. GWT also has a Java-to-JavaScript compiler, which translates the Java programming code into JavaScript. It also provides the ability to use Google APIs, and to build HTML5 and CSS3 web applications.

⏳ When ?

Google Web Toolkit (GWT) has been in use since it was made open source by Google in 2006. It's been continually updated and improved since then, with the latest major release (2.9.0) coming in May 2020.

⚙️ Technical Explanations

Google Web Toolkit (GWT) is an open-source development toolkit for building and optimizing robust browser-based applications. GWT's core feature is its Java to JavaScript compiler, which allows developers to write complex front-end applications in Java. The compiler then translates this Java code into highly efficient JavaScript that is compatible across all browsers, including mobile browsers.

Developers can benefit from the GWT Software Development Kit (SDK), which includes a set of core Java Application Programming Interfaces (APIs) and Widgets. With these tools, developers can write Asynchronous JavaScript and XML (AJAX) applications in Java. These applications are then compiled to highly optimized JavaScript that can operate across a multitude of devices, ensuring broad accessibility for the developed applications.

Moreover, GWT includes tools for direct interaction with JavaScript code. This feature is particularly beneficial as it allows developers to utilize pre-existing JavaScript libraries and frameworks, thereby enhancing the functionality and efficiency of their applications.

GWT is popular for its productive development and powerful performance for Java software development teams. It enables developers to build complex web-based applications without requiring expertise in front-end technologies like JavaScript optimization and responsive design. Furthermore, GWT provides a unique web browser, known as GWT Development Mode, where developers can debug their GWT applications just like any other Java application.

GWT has been in use since 2006 when Google made it open source. It has been consistently updated and improved, with the latest major release (2.9.0) in May 2020. This highlights the active development and relevance of GWT in the modern web development landscape.

Here's a simple example of a "Hello, World!" application using Google Web Toolkit (GWT):

First, we create a new GWT project:

$ webAppCreator -out HelloWorld com.example.HelloWorld

This command creates a new GWT project named HelloWorld in the HelloWorld directory. com.example.HelloWorld is the fully qualified name of the module that serves as the starting point for your application.

Navigate to the HelloWorld directory and inspect the src/com/example/HelloWorld/HelloWorld.java file:

package com.example.helloworld.client;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.RootPanel;

public class HelloWorld implements EntryPoint {

    public void onModuleLoad() {
        Label label = new Label("Hello, World!");
        RootPanel.get().add(label);
    }
}

In this file, we have a simple GWT application. HelloWorld class implements the EntryPoint interface. onModuleLoad method is the entry point method, similar to the main method in a standard Java program. Within this method, we create a Label widget with the text "Hello, World!" and add it to the RootPanel.

To compile this application to JavaScript, navigate to the HelloWorld directory and run:

$ ant build

This will generate JavaScript code from your Java application.

To run the application in the GWT Development Mode, use:

$ ant devmode

Then, in the GWT Development Mode window that pops up, click 'Launch Default Browser' to see your application in action.

This is a simple example, but GWT can be used to create much more complex web applications, integrating with existing JavaScript libraries and Google APIs, building HTML5 and CSS3 web applications, and much more.