5 pillars of a successful Java Web application

Swamped by new JavaScript frameworks that are born every 6 months? What about maintaining your enterprise application for longer than the 2-year lifecycle of these frameworks? This talk can provide you with insightful answers, share challenges and the solutions through the 5 pillars of a successful Java Web application extracted directly from the development of jBPM and Drools web workbenches.
Come and join me for this talk. I'll share how we're able to keep a 7-year old Java application, that combines modern techniques with a legacy codebase of more than 1 million LOC, up-to-date with an agile, sustainable and evolutionary web approach. Some key points you'll learn are:
* The advantages of Contract Based Development instead of a Framework Centric Development;
* How static typing is a central point in a huge web application;
* How we use the same programming model (Java EE) on the backend and browser ;
* How a Java to JS APIs allow your application to evolve over time and support heterogeneous (polyglot) web frameworks;
* The importance of a clean and unified UI framework for your enterprise architecture and how to do it on Java;

Transcript

1. 5 pillars of a successful
   Java Web application
   Eder Ignatowicz
   Sr. Software Engineer @ Red Hat
   

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3. Which backend architecture?
   

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4. Java 9 modular, Reactive,
   Microservices, Vert.x
   Drools, Spring Boot,
   Zookeeper, Spark
   

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5. And on the front-end?
   

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10. Javascript Development
    is complex
    

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11. Web Javascript
    development is complex
    

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12. Web development
    will stay complex
    

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18. Which web stack?
    

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19. Which web architecture is most
    doable for this problem?
    

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20. 5 pillars:
    Large scale application
    Full stack Developers
    UX Integration
    5~10 years Life-Span
    Interoperability
    

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21. 5 pillars:
    Large scale application
    Full stack Developers
    UX Integration
    5~10 years life-span
    Interoperability
    

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22. Large Scale Application
    1mi+ lines of web code
    5 projects
    ~150 subprojects
    ~30 devs
    Code base of 7+ years
    

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23. Large Scale Application
    Static
    Typing
    

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24. Large Scale Application
    Refactoring
    

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27. Large Scale Application
    JS Transpilers
    

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29. .java
    javac .class
    

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34. GWT
    <3
    

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35. GWT
    The Good Parts
    

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36. GWT GOOD PARTS
    Java to JavaScript
    

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37. GWT GOOD PARTS
    java.* emulation
    

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38. GWT GOOD PARTS
    DOM APIs
    

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39. GWT GOOD PARTS
    Java 8
    “client side"
    

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40. Java 8
    List myList =
    Arrays.asList("Java7", “Java8",
    "Java6", "Kotlin");
    myList
    .stream()
    .filter(s -> s.startsWith("J"))
    .map(String::toUpperCase)
    .sorted()
    .forEach(Console::log);
    Prints:
    JAVA6
    JAVA7
    JAVA8
    

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41. GWT GOOD PARTS
    Dev Tools
    

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43. GWT GOOD PARTS
    JS Interop
    

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44. JS INTEROP - CONSUME
    Java
    @JsType(isNative = true)
    public abstract class JQuery {
    @JsMethod(namespace=GLOBAL)
    public native static JQuery $(String selector);
    public native JQuery css(String prop, String val);
    public native JQuery attr(String name, String val);
    }
    Java
    import static jquery.JQuery.$;
    // ...
    $("ul > li").css("color", "red").attr("data-level", "first");
    

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45. JS INTEROP - EXPOSE
    Java
    package foo;
    @JsType
    public class Dora {
    public boolean late = true;
    public Dora() {}
    public String auAu() { return "Hello QCon!";}
    }
    JavaScript
    var dora = new foo.Dora();
    if (dora.late) {
    alert(dora.auAu());
    }
    

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46. Large Scale Application
    Refactoring
    

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47. 5 pillars:
    Large scale application
    Full stack Developers
    UX Integration
    5~10 years life-span
    Interoperability
    

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48. Devs Full Stack
    “End-to-end” developers
    

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49. Devs Full Stack
    Shared Programming Model
    

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50. Devs Full Stack
    “Java EE” in browser
    

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52. ERRAI
    CDI on Browser
    

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53. @Dependent
    public class ProjectsView {
    @Inject
    Document document;
    @Inject
    @DataField( "projects-view" )
    Div view;
    @Inject
    @DataField( "new-project" )
    Button newProject;
    @Inject
    @DataField( "projects-list" )
    UnorderedList projectsList;
    @Inject
    Instance projects;
    CDI NO BROWSER
    

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54. if (!filter.doFilter(event)) {
    if (event.kind().equals(StandardWatchEventKind.ENTRY_ADD)) {
    resourceAddedEvent.fire(buildEvent(ResourceAddedEvent.class,
    event).getK2());
    }
    …
    }
    

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55. public void onNewFile(@Observes ResourceAddedEvent event)
    {
    Window.alert(
    "ResourceAddedEvent:" +
    event.getPath().toURI() +
    " ['" + event.getMessage() + “‘]");
    }
    

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57. Server
    Browser
    Browser Browser
    Browser
    Long Polling
    Web Sockets
    SSE
    ERRAI BUS
    

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58. Devs Full Stack
    Shared Programming Model
    

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59. 5 pillars:
    Large scale application
    Full stack Developers
    UX Integration
    5~10 years life-span
    Interoperability
    

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60. 
    Pizza Types
    
    
    
    
    
    
    $
    
    
    
    
    Size
    
    
    
    Small
    
    Medium ( + 2$ )
    
    Large ( + 3$ )
    
    
    Extra Toppings
    
    
    
    
    
    
    
    
    
    if ( j == 0 && remainder > 0 ) {
    %>
    
    
    
    1 ) { %>
    
    
    
    
    
    
    
    
    
    Each extra topping is 0.65$
    
    
    ...
    

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61. {{title}}
    My favorite hero is: {{myHero}}
    Heroes:
    
    
    {{ hero }}
    
    
    

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62. 
    
    
    data-field="new-project">
    New Project
    
    
    

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63. @Dependent
    @Templated
    public class ProjectsView {
    @Inject
    @DataField( "projects-view" )
    Div view;
    @Inject
    @DataField( "new-project" )
    Button newProject;
    @Inject
    @DataField( "projects-list" )
    UnorderedList projectsList;
    }
    ERRAI UI
    

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65. 
    
    
    
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67. UX Integration
    Leave the HTML/CSS in peace
    

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68. 5 pillars:
    Large scale application
    Full stack Developers
    UX Integration
    5~10 years life-span
    Interoperability
    

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70. Architecture
    Hexagonal Architecture - Alistair Cockburn
    Onion Architecture - Jeffrey Palermo
    DCI - James Coplien e Trygve Reenskaug.
    BCE - Ivar Jacobson
    Clean Architecture - Robert C. Martin
    

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71. Principles
    Not coupled to Frameworks
    Testable
    Not coupled with UI technology
    Not coupled with Database
    Independent of another systems
    

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73. "Architecture is about intent.
    We have made it about
    frameworks and details”
    Robert C. Martin
    

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74. APPFORMER VFS
    Use Cases
    VFS
    API
    Regular FS
    Clustering
    GIT FS
    

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76. Which web framework
    should I use?
    

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77. Which JS framework?
    

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78. JS framework
    choice
    Years
    1 2 3 4 5 6
    First
    Release
    Danger
    0
    

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79. What’s next for Angular 1.x?
    
    "In all honesty, no one really knows what will happen"
    https://toddmotto.com/future-of-angular-1-x
    

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80. 1 2 3 4 5 6
    Years
    Deliver
    JS
    Framework
    Choice
    Learning
    Curve
    Project Canceled
    or new version
    is incompatible
    Rewrite on the new
    JS framework
    Learning
    Curve
    Project Canceled
    or new version
    is incompatible
    Rewrite on the new
    JS framework
    Learning
    Curve
    

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81. "A good architecture allows
    volatile decisions to be easily
    changed”
    Robert C. Martin
    

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82. What if I dealt with the volatility of
    JS frameworks as a fact?
    

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85. Programming Model
    Components:
    - Screen
    - Editors
    - Perspectives
    - Popups
    

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86. Programming Model
    LifeCycle:
    - OnStart
    - OnSave
    - IsDirty
    - OnClose
    - OnFocus
    - OnLostFocus
    - OnMayClose
    - OnReveal
    

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87. Perspective
    Editor
    Screen Screen
    

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88. Contract Based
    Screen -> Interface WorkbenchScreenActivity
    Editor -> Interface WorkbenchEditorActivity
    Perspective -> Interface PerspectiveActivity
    

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89. Perspectives
    Appformer
    Lookup
    Perspective
    ERRAI
    CDI BEAN
    MANAGER
    Scan all
    Perspective Activity
    Implementations
    GWT
    Perspective
    Adapter
    OLD GWT
    WIDGET
    ERRAI UI
    Perspective
    Adapter
    Plain HTML Errai
    UI
    

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90. 7 years old code with
    “old school” GWT
    

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91. HTML 5 canvas
    fresh code
    

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92. 5~10 years life-span
    The Web architecture should be
    treated with the same respect as
    you treat your backend.
    

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93. 5 pillars:
    Large scale application
    Full stack Developers
    UX Integration
    5~10 years life-span
    Interoperability
    

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94. @WorkbenchPerspective(identifier = "HomePerspective",
    isDefault = true)
    @Templated
    public class HomePerspective implements IsElement {
    @Inject
    @DataField
    @WorkbenchPanel(parts = "MoodScreen?uber=fire&uber1=fire1")
    Div moodScreen;
    @Inject
    @DataField
    @WorkbenchPanel(parts = "HomeScreen?uber=fire")
    Div homeScreen;
    @Inject
    @DataField
    @WorkbenchPanel(parts = "AnotherScreen")
    Div anotherScreen;
    } @JsType
    public interface PerspectiveActivity{
    PerspectiveDefinition getDefaultPerspectiveLayout();
    @Override
    default String getName() {
    return getDefaultPerspectiveLayout().getName();
    }
    boolean isDefault();
    Menus getMenus();
    ToolBar getToolBar();
    }
    

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96. function TodoCtrl($scope) {
    $scope.placeText = "MiscellaneousFeatures";
    $scope.todos = [
    {text: 'learn angular', done: true},
    {text: 'build an angular app', done: false}
    ];
    $scope.addTodo = function () {
    $scope.todos.push({text: $scope.todoText, done: false});
    $scope.todoText = '';
    };
    $scope.remaining = function () {
    var count = 0;
    angular.forEach($scope.todos, function (todo) {
    count += todo.done ? 0 : 1;
    });
    return count;
    };
    $scope.archive = function () {
    var oldTodos = $scope.todos;
    $scope.todos = [];
    angular.forEach(oldTodos, function (todo) {
    if (!todo.done) {
    $scope.todos.push(todo);
    }
    });
    };
    $scope["goto"] = function () {
    $goToPlace($scope.placeText);
    };
    }
    
    
    
    {{remaining()}} of {{todos.length}} remaining [
    archive ]
    
    Todos
    
    
    {{todo.text}}
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    $registerPlugin({
    id: "my_angular_js",
    type: "angularjs",
    templateUrl: "angular.sample.html",
    title: function () {
    return "angular " + Math.floor(Math.random() * 10);
    },
    on_close: function () {
    alert("this is a pure JS alert!");
    }
    });
    

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97. Perspectives
    Appformer
    Lookup
    Perspective
    ERRAI
    CDI BEAN
    MANAGER
    Scan all
    Perspective Activity
    Implementations
    GWT
    Perspective
    Adapter
    OLD GWT
    WIDGET
    ERRAI UI
    Perspective
    Adapter
    Plain HTML Errai
    UI
    Angular
    Perspective
    Adapter
    Angular native
    Perspective
    Any JS
    Perspective
    Adapter
    Any JS
    Framework
    

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98. Angular JS Screen
    

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99. Creating Components
    in Runtime
    

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102. 5 pillars:
     Large scale application
     Full stack Developers
     UX Integration
     5~10 years life-span
     Interoperability
     

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103. Web development
     is complex
     

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104. Web applications are
     important pieces of
     our architecture
     

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105. Principles
     Not coupled to Frameworks
     Testable
     Not coupled with UI technology
     Not coupled with Database
     Independent of another systems
     

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106. Software architecture
     is trade-offs exercise
     

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107. 5 pillars:
     Large scale application
     Full stack Developers
     UX Integration
     5~10 years life-span
     Interoperability
     

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108. Eder Ignatowicz
     @ederign
     http://bit.ly/5-pillars-web
     

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