The favicon can be set in the AppShellConfigurator by adding the favicon in the method configurePage.

Setting favicon in AppShellConfigurator
    public void configurePage(AppShellSettings settings) {
        settings.addFavIcon("icon", "favicon-192.png", "192x192");

If you are deploying your application under a context root, you may need to use "../favicon.ico" instead.

For Spring Boot applications, the icon files should be in src/main/resources/static.

If you are deploying to an application server, they need to be in src/main/webapp.