Google Web Toolkit 2.0 Adds Performance ToolsGoogle Web Toolkit 2.0 Adds Performance Tools

At its latest Campfire One event on Tuesday evening, Google introduced version 2.0 of the Google Web Toolkit (GWT), a set of programming tools designed to simplify the development of Web applications.

GWT 2.0 includes several new tools, the most significant of which is Speed Tracer, a Google Chrome extension that allows developers to profile Web app performance and identify sources of slowness.

Google and others working on browsers like Firefox have succeeded in making JavaScript much faster.

But now, says Google product manager Andrew Bowers, HTML and CSS code often lead to performance bottlenecks.

Speed Tracer, he said, "allows you to profile the application over time and see what's going on."

The project's goal, he says, was to make a tool not just for profiling but for understanding, so developers aren't left trying to sort through massive dumps of performance data.

According to Bruce Johnson, the project's technical lead, Speed Tracer has helped accelerate some Web apps by a factor of 3x to 5x.

GWT 2.0 also is now capable of code splitting, which allows large JavaScript files to be broken apart and downloaded in pieces as needed.

This prevents Web app load delays that occur when waiting for large JavaScript files to download.

The code-splitting capability follows from the development of Google Wave, which involved JavaScript files as large as 1.4 MB.

"For anyone who has tried to split JavaScript themselves this is a welcome change," said Bowers.

In addition, GWT includes an improved way to build interface code called UiBinder, which provides separates visual code elements from application logic.

Other refinements are discussed on the Google Web Toolkit blog.