The Java alternative to Javascript
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GWT 2.8.x - 3.0.x provides a Java alternative to JavaScript for building web applications. It has evolved over time from addressing issues with early JavaScript and browsers to embracing modern JavaScript. GWT 3.0 will focus on the JavaScript ecosystem through a new compiler called J2CL that transpiles Java to JavaScript for better integration. This positions GWT to remain relevant for building frontend applications by leveraging the large Java and modern JavaScript ecosystems.
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JS: Crazy type conversion](https://image.slidesharecdn.com/gwt-madrid-171103093314/85/The-Java-alternative-to-Javascript-12-320.jpg)
![Elemental2 - new Browser API
public class SimpleApp {
public static void main(String[] args) {
window.addEventListener("load", evt -> install());
}
private static void install() {
final HTMLButtonElement button = (HTMLButtonElement) document.createElement("button");
button.textContent = "Click me";
button.addEventListener("click", evt1 -> {
button.parentNode.removeChild(button);
console.log("Button has been removed.");
});
document.body.appendChild(button);
}
}](https://image.slidesharecdn.com/gwt-madrid-171103093314/85/The-Java-alternative-to-Javascript-39-320.jpg)
The Java alternative to Javascript
- 1. GWT 2.8.x - 3.0.x The Java alternative to Javascript Manolo Carrasco +ManuelCarrascoMonino @dodotis
- 2. About me
- 3. Agenda ● A little bit of context of Vaadin ● Spooky JS ● History of GWT ● Present of GWT ○ LTM projects ○ Modern web ● Is GWT dead ○ State of the Frontend ○ J2CL the future
- 4. FIGHT FOR SIMPLICITYthinking of U and I
- 5. - Vaadin is a development platform for web applications that prioritizes ease of development and uncompromised end user experience. - The Vaadin platform consists of a comprehensive set of web components, a Java web framework, configurable themes, tools and a set of app templates. Vaadin
- 6. Architecture Developer Space Provided by Vaadin JVM Browser
- 7. Java Lang JVM ecosystem libs, IDEs ... Developer space GWT vs Vaadin Java Lang JVM ecosystem libs, IDEs ... Scala, Groovy...
- 8. MillStone 3.0 IT Mill 4.0 IT Mill 5.0 2002 2007 2008 2018 2013 2009 Vaadin 6.0 Vaadin 7.0 2017 Vaadin 8.0 Vaadin 10 Vaadin: a 18y whisky
- 11. JS: What is the issue here? idx might be a String
- 12. "0" == 0 "0" === 0 [] == [] [] == ![] ![] +[] 2 == [2] +[2] [2] + '' +([2] + '') +[2,3] +[2,3] + '' '2' + 1 '2' - 1 '2' - - 1 +true +false true + true parseInt(2) parseInt('2') parseInt('aaa') parseInt(9999999999999999) typeof NaN 0.1 + 0.2 == 0.3 'I am String' instanceof String String('I am String') instanceof String 3 > 2 2 > 1 3 > 2 > 1 3 > 2 >= 1 1 < Number.MAX_VALUE -1 < Number.MAX_VALUE -1 < Number.MIN_VALUE Number.MAX_VALUE Number.MIN_VALUE Math.max(1,2,3) Math.min(1,2,3) Math.max() > Math.min() Math.max() Math.min() String instanceof String Math instanceof Math typeof null null instanceof Object JS: Crazy type conversion
- 14. GWT's mission is to radically improve the web experience for users by enabling developers to use existing Java tools to build no-compromise AJAX for any modern browser. GWT Mision A high-level language allows the Developer not to miss out on low-level details and reuse existing ecosystem GWT Productivity 2006
- 15. 2006 Context - Browsers - No Debug tools - IE6, FF 1.5, Safari 2, Opera 9, No Chrome - Incipient CSS (No animations, No rounded …) - No RIA, No SPI - No Smartphones - Low performance PCs (256Mb, Single Core ...) - JavaScript - ES-3, No Standard XHR, No DOM traversing - No IDE. No Refactoring, No Tests, No Libraries, No packaging ... - No Runtime (V8) - Java 1.4, no generics, no annotations
- 16. 2006 Context - Compiling to JavaScript was not a thing - GWT pioneered the idea. - Then came: CoffeeScript, Dart, TypeScript, …
- 17. Advantages of a Compiler Separate the maintainability of the code from the effectiveness of the executable. - The handwritten JS was verbose and slow - The solution is not to look for conventions in the javascript code written by hand, it is to create a level of separation so that both are not compromised (maintainability, effectiveness). Remove the bad parts while keeping the good stuff
- 18. Advantages in Compile Time - Common errors are correctable at compile time and not in execution time. - Functionalities can be injected. - Peculiarities / Hacks for each browser - Assets bundling and compression - Code Splitting and async loading - Conversion and obfuscation server objects ↔ client - Versioning, Minimisation
- 19. The basis of GWT - The heart of GWT is the compiler, Java -> JavaScript - Only supports a subset of the Java language - The resulting code is JavaScript, single-threaded code. - Creates a separated, obfuscated and optimised JavaScript implementation for each supported browser. - Takes into account browser specific features, bugs, issues and performance optimizations - But the toolkit has plenty of tools (dev, build, test, libs)
- 20. Innuvo 1.0.21 1.3.3 O.S 2005 2006 2007 2018 2010 2009 2.0 UIB OOPHM 2.1 MVP RF 2011 2.2 Designer 3.0 J2CL GWT a 12y whisky 2012 Grid 2.4 2013 2.5 SDM 2017 2.8 J8 JSi E22014 2.6 J7
- 21. The present of GWT
- 22. GWT is Popular in the Java Web 2016 2012
- 23. Stable Platform
- 24. Reliable
- 25. Good Tools & Ecosystem
- 26. High Quality and Mature
- 28. For Big Teams & Big Projects
- 29. But
- 31. Outdated docs
- 32. Obsolete Stuff ↝ Generators ↝ Widgets, Elements, JSO ↝ RPC ↝ RF ↝ AutoBeans ↝ UiBinder ↝ JSNI ↝ Classic DevMode ↝ Ant ↝ Designer
- 34. A project with few Contributors
- 35. Unmaintained libs GWT spring react
- 36. Hard to Interact with JS - Not Anymore - JsInterop - Elemental2
- 37. @JsType(isNative = true) public abstract class JQuery { @JsMethod(namespace=GLOBAL) public native static JQuery $(String selector); public native JQuery css(String prop, String val); public native JQuery attr(String name, String val); } import static jquery.JQuery.$; // ... $("ul > li").css("color", "red").attr("data-level", "first"); Java Java Use native JsType to use any existing JavaScript library. Use it like JavaScript JsInterop Consume
- 38. package foo; @JsType public class Bar { public boolean bool = true; public Bar() {} public String foo() { return "Hello GWTCon!";} } var bar = new foo.Bar(); if (bar.bool) { alert(bar.foo()); } JavaScript Expose your Object to JavaScript world. JavaScript can use your public API of exposed Java objects. Java JsInterop Export
- 39. Elemental2 - new Browser API public class SimpleApp { public static void main(String[] args) { window.addEventListener("load", evt -> install()); } private static void install() { final HTMLButtonElement button = (HTMLButtonElement) document.createElement("button"); button.textContent = "Click me"; button.addEventListener("click", evt1 -> { button.parentNode.removeChild(button); console.log("Button has been removed."); }); document.body.appendChild(button); } }
- 40. Status of the current GWT GWT 2.8.x - Big Java artifacts (no split in modules) - Stable & Long Term API Support - No new Features planned - Prepared for JS - JsInterop - Elemental2 - Large ecosystem - 2.8 is stable and available for foreseeable future
- 41. Long Term Support Applications LTS Apps
- 42. 2.8.x is perfect for Long Term Apps
- 43. - Avoid legacy modules - Most Widgets, RPC, RF, etc - Design with UIBinder and CSS3 - Use J8 syntax, collapse browser permutations. - Select good 3rd party libs - Gwt-material, Gwt-bootstrap, Gwt-query - Use JsInterop for json data or Resty-GWT Good Practices for LTS apps in 2.8.x
- 44. GWT is PWA
- 45. Decorate the host page with CSS3 App Shell
- 46. GWT nature is SPI and RIA App Like Iterations
- 48. HTTPS: simply works GWT linkers: unique random names Secure & Fresh Updates
- 49. Responsive UI - Permutation per device - Responsive UI libs
- 50. - GWT already have - Code splitting - Code removal - Permutations Fast Loading
- 51. Offline GWT is client side -> Works Offline
- 52. - Use Responsive Widgets Gwt-bootstrap Gwt-material Gwt-polymer-elements Recipe 1 - Responsiveness
- 53. - Re-use UI Componens: JsInterop - Easier development and sharing - Lazy load components when needed - Cache components for ever - Use the platform: Elemental 2.0 - Thanks to JsInterop, to interact with platform is easy - Use Elements instead of Widgets - Not need of gwt wrap libraries Recipe 2 - Fast loading
- 54. - Add a static Web App manifest - Generate service-worker - Disable old browsers: <set-property name="user.agent" value="safari,gecko1_8" /> - Don’t use permutations: <collapse-all-properties value="true" /> - Avoid random JS names <add-linker name="sso" /> - Use the sw-precache CLI Recipe 3 - Offline first
- 55. - Use out-of-the-box solutions - PouchDB + CouchDB - Gwt-pouchdb - Vaadin-pouchdb (via gwt polymer) - Firebase - Gwt-firebase (xplatform) - Polymerfire (via gwt polymer) Recipe 4 - Data Offline
- 56. - Inbox - G Suite - Google Docs - Google Flights - Closure - Vaadin Flow internals How uses modern GWT
- 57. GWT Transition path for the Future
- 58. The Near future of GWT GWT 2.9.x - Modular (split in small artifacts) - Parts might be transferred to, or taken by the community - Expect changes and new Features in API - Removing browsers, jsni, moving namespaces, etc - Replacing generators with Annotation Processors - But maintaining backwards compatibility - Prepared for the JavaScript wild - Expect tools for sharing with GWT 3.0
- 59. 2.9.x might be your Transition Path
- 60. - Use min set of modules, start with Core.gwt.xml - Forget Classic Widgets and Element - Replace classic DOM with Elemental2 - #useThePlatform as much as possible - Check 3rd party modules not to import User.gwt.xml - Design the UI using Js reusable widgets - Web components (gwt-polymer) - Html templates (elemento or polymer) - Decouple business logic from UI Best practices for the Transition
- 61. The Future of GWT
- 62. Frontend: State of the art
- 63. We are in the JavaScript Era
- 64. Popularity of Web Platforms
- 65. Huge ecosystem
- 66. Good dev tools in JS
- 67. JS also runs everywhere
- 68. How is GWT in this jungle
- 69. Lot of reactions, Is GWT Dead?
- 70. GWT reasons, not valid anymore - For the Browser (2006) - Huge diffs between vendors (IE6) - memory limitations (256Kb RAM PCs) - Related with JavaScript (2006) - No way to debug JS - No tooling for JS optimisation and obfuscation - No way of modularising / managing dependencies - No IDE. No Testing tools. Slow runtime. - Java Specific (2006) - Same language client/server - More developers than JavaScript
- 71. - The Java Language is the strong Key of using GWT GWT reasons nowadays
- 72. Embrace the JavaScript world
- 73. GWT 3.0 is for the frontend chaos - New compiler and tooling - J2CL - Runtime JVM, Node or both? - Build system bazel, maven, npm ? - Big changes in API and emulated JRE - Prepared for the platform - JsInterop - Elemental2 - Comes with a different DX paradigm
- 74. J2CL Pronounced “Jackal” Shares features with the GWT compiler ● JsInterop ● Java8 ● Java standard library (JRE) ● Elemental2
- 75. J2CL Source to source transpiler - Takes Java 8 code as input and outputs readable ES6 with JsDoc Closure style annotations Transpiles one Java class at a time Optimizations happen in Closure compiler Code generation happen in Java annotation processors Targeting modern Js features, blazing fast
- 76. Transpiler @JsType public class Hello { public String message() { return "GWTCon!"; } public static String getMessage() { return "Hello " + new Hello().message(); } } class Hello extends java_lang_Object { /** * @public */ constructor() { super(); } /** * @return {?string} * @public */ message() { return "GWTCon!"; } /** * @return {?string} * @public */ static getMessage() { return "Hello " + new Hello().message(); } };
- 77. J2CL - Sharing Code Java JavaScriptJ2CL JavaScriptClosure Optimized JavaScript
- 78. J2CL + Closure → Optimisation
- 79. Two possible paths for J2CL ➔ Classic Java Development flow ◆ Java IDE ◆ Java dependency artifacts (.jar) ◆ Java Build tools mvn, gradle, j2cl, closure, linker ◆ JVM for server side and testing tools ➔ Just a transpiler to JavaScript ◆ Java IDE ◆ JS dependencies (.js) ◆ JS Build tools npm, closure-compiler-js ◆ node-js for server side ◆ JS testing tools
- 80. A java transpiler in the JS world NODE ECOSYSTE M npm,gulp,*.js , Java IDE mvn, jar, Java IDE JVMJAVA NODE npm, gulp, *.js, Java IDE JAVA