Optimizing GWT Application Size - Tutorial

Welcome to this tutorial on optimizing the size of GWT applications. Optimizing the size of your GWT application is essential for improving performance and reducing load times. In this tutorial, you will learn effective techniques and best practices to minimize the size of your GWT application and optimize its overall performance.

Introduction to Optimizing GWT Application Size

GWT applications can sometimes become large and bulky due to the inclusion of unnecessary code and resources. This can negatively impact the performance of the application, especially in terms of download and startup times. Optimizing the application size involves identifying and eliminating redundant or unused code, reducing resource sizes, and employing techniques that minimize the overall footprint of the application.

Example: Code Splitting

One technique to optimize the size of a GWT application is code splitting. Code splitting allows you to split the application into multiple fragments, and load them dynamically as needed. This can significantly reduce the initial download size of the application and improve the initial load time.

// Code Splitting Example
MyModule.java:

@EntryPoint
public class MyModule implements EntryPoint {
  public void onModuleLoad() {
    // Split the code into two fragments: MainFragment and ExtraFragment
    GWT.runAsync(new RunAsyncCallback() {
      public void onSuccess() {
        // Load and display the main fragment
        MainFragment main = new MainFragment();
        main.display();
      }

      public void onFailure(Throwable caught) {
        // Handle failure
      }
    });
  }
}

MainFragment.java:

public class MainFragment {
  public void display() {
    // Display the main fragment
    // ...
  }
}

ExtraFragment.java:

public class ExtraFragment {
  // Additional functionality in the extra fragment
  // ...
}

In this example, the application is split into two fragments: the main fragment and the extra fragment. The main fragment is loaded and displayed initially, while the extra fragment is loaded only when needed. This allows for a smaller initial download size, as the extra functionality is loaded on-demand.

Step-by-Step Guide

Step 1: Eliminate Unused Code and Resources

Review your codebase and remove any unused or redundant code and resources. Unused code can be safely removed to reduce the application size without affecting functionality. Consider removing unused dependencies, classes, methods, and CSS stylesheets.

Step 2: Enable Code Splitting

Implement code splitting to break down your application into smaller fragments that can be loaded dynamically. Identify areas of your application that can be split and use the GWT code splitting mechanism, such as the `GWT.runAsync()` method, to load fragments on-demand.

Step 3: Optimize Resource Sizes

Minimize the size of your resources, such as images, CSS files, and JavaScript libraries. Use tools like image compression, CSS minification, and JavaScript obfuscation to reduce the size of these resources without sacrificing quality or functionality.

Step 4: Use Compile-time Optimizations

Take advantage of compile-time optimizations provided by GWT, such as dead code elimination and method inlining. Enable these optimizations in your GWT configuration to remove unused code and inline small methods, resulting in a smaller and more efficient compiled output.

Common Mistakes to Avoid

• Not removing unused code and resources, leading to unnecessary bloat.
• Overlooking code splitting as a technique to reduce initial download size.
• Ignoring resource optimization, such as image compression and minification.
• Not enabling compile-time optimizations provided by GWT.

Frequently Asked Questions (FAQs)

1. Can I optimize the size of my GWT application without affecting its functionality?

Yes, you can optimize the size of your GWT application by removing unused code and resources, employing code splitting techniques, and optimizing resource sizes. These optimizations focus on reducing the application size without impacting its functionality or user experience.

2. How does code splitting work in GWT?

Code splitting in GWT involves breaking down the application into smaller fragments, which can be loaded dynamically on-demand. This helps reduce the initial download size of the application and improves the application's startup time.

3. Are there any tools available to help optimize resource sizes in GWT?

Yes, there are several tools available for optimizing resource sizes in GWT. Tools like image compression tools (e.g., ImageOptim, TinyPNG), CSS minifiers (e.g., YUI Compressor, CSSNano), and JavaScript obfuscators (e.g., Closure Compiler) can be used to minimize the size of images, CSS files, and JavaScript libraries, respectively.

Summary

In this tutorial, you learned how to optimize the size of GWT applications to improve performance and reduce load times. By eliminating unused code and resources, employing code splitting techniques, optimizing resource sizes, and using compile-time optimizations, you can significantly reduce the size of your GWT application. Following these best practices will result in faster loading times and an overall better user experience.