Google Web Toolkit vs JSweet

Google Web Toolkit (GWT) is a free, open-source Java framework for building AJAX web applications. Its compiler converts Java applications into JavaScript and HTML for browser use, and the SDK includes the core libraries and compiler. Deferred binding generates browser-specific code at compile time, while the compiler can create separate application versions for different browsers and languages. Applications can communicate asynchronously with servers through GWT RPC or JSON. An Eclipse plugin provides IDE support and an option to install the SDK. The developer guide covers deployment to Google App Engine, JUnit unit testing and Emma code coverage; documentation also includes SafeHtml guidance for XSS prevention and GWT RPC XSRF protection. GWT is licensed under Apache 2.0 for non-commercial, commercial and enterprise applications. Version 2.13.1 is listed for Windows, Mac OS X and Linux. Development mode and the compiler periodically send a timestamp ID and product version to Google; Google says it does not log cookies or personal information. The webAppCreator utility has been deprecated since version 2.11.0.

JSweet converts Java programs into TypeScript and JavaScript for browsers, mobile Web views, or Node.js. It uses Oracle's Java compiler alongside Microsoft's TypeScript compiler to generate type-checked JavaScript. The project describes the output as regular JavaScript that can work directly with JavaScript programs and libraries. Listed language features include Java-to-TypeScript syntax mapping, Java constructs, async/await, and ECMAScript targets from ES3 to ES6. JSweet lists support for more than 1,000 JavaScript libraries, frameworks, and plugins, packaged as Maven artifacts called candies. It provides Eclipse, Maven, and Gradle plugins, and names Angular, Cordova, Node.js, and Three.js among example integrations. Generated programs can use CommonJS, AMD, or UMD modules and run in browsers or Node.js. A debug mode supports debugging Java code in a browser. Setup instructions call for Git, Node.js, and Maven, then use Maven to generate JavaScript from a quickstart project. JSweet is open source and free, and is presented for Java developers building web and mobile HTML5 applications with JavaScript libraries and frameworks.