Interview Questions.

Question 1. What Is Wicket Framework?

Answer :

Wicket is one of the most recent in a long line of Java web development frameworks.Wicket is part-basedframework, which places it in stark contrast to some of the earlier solutions to the sometimes monotonous project of internet programming.Wicket builds on top of Sun's servlet API. Wicket is ordinarily eliminated from the request/reaction nature this is inherent with the net and Servlets. Instead of building controllers that ought to service many customers and threads concurrently, taking in requests, returning responses, and by no means storing any state, the Wicket developer thinks in phrases of stateful components. Instead of making a controller or action elegance, she or he creates a page, places components on it, and defines how each thing reacts to consumer input.
It is a lightweight issue-based totally net utility framework for the Java programming.
Question 2. What Are Wicket Models?

Answer :

A Model holds a cost for a issue to show and/or edit :

Simple Models
Dynamic Models
Property Models
Compound Property Models
Wrapped Object Models
Resource Models
Detachable Models
Chaining fashions
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Question 3. What Are The Ways To Create A Page In Wicket?

Answer :

There are 2 methods to Create New Wicket Page.

Create a Page Extending "WebPage" Class.
Create a Page Extending  "BasePage" ( BasePage Should Extend "WebPage").
IF you're using first Way you have to Create Whole page with thier Header,Footer and different elements
and that HTML report's content material can be large (complicated).This is an Unreliable way to create Page. Suppose you need to trade some content in Header component then you need to edit all pages that having Header Content 
If you are using 2d way, first Create your BasePage then you can enlarge those page to other even as growing new web page. In that page you need to add handiest Body part (Content that you want to show on that Page) Using <wicket:child />
Question 4. What Is About Web Application In Wicket?

Answer :

A internet application is a subclass of Application which associates with an instance of WicketServlet to serve pages over the HTTP protocol. This magnificence is meant to be subclassed with the aid of framework customers to outline a web utility.

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Question 5. What Is Base Class For Html Pages?

Answer :

Base magnificence for HTML pages: Webpage Class.

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Question 6. Dependency To Start Wicket?

Answer :

<dependency>

<groupid>org.Apache.Wicket</groupid>

<artifactid>wicket</artifactid>

<version>1.Four.17</version>

</dependency>

Wicket need SLF4J !

You need to consist of the slf4j logging implementation, otherwise Wicket can be didn't begin.

Wicket need aid filter

Remember to feature the useful resource clear out, Wicket puts all documents in identical package folder, if you didn’t define the useful resource filter to consist of the whole lot “<include>*</include>” , “html”, “houses” or other assets documents may also failed to reproduction to the appropriate goal folder.

Question 7. How To Create A Textfield In Apache-wicket?

Answer :

very last TextField username = new TextField("username",Model.Of(""));

username.SetRequired(actual);

username.Upload(new Username  Validator());

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Question eight. How To Submit A Form In Apache-wicket?

Answer :

Form<?> shape = new Form<Void>("userForm") 

  @Override

blanketed void onSubmit() 

  very last String usernameValue = username.GetModelObject();

  PageParameters pageParameters = new PageParameters();

pageParameters.Upload("username", usernameValue);

setResponsePage(SuccessPage.Magnificence, pageParameters);

  

 ;

Question 9. Tell Me The Example Of Username Validation In Apache-wicket?

Answer :

import org.Apache.Wicket.Validation.CompoundValidator;

import org.Apache.Wicket.Validation.Validator.PatternValidator;

import org.Apache.Wicket.Validation.Validator.StringValidator;

 public magnificence UsernameValidator extends CompoundValidator<String> 

  non-public static very last lengthy serialVersionUID = 1L;

  public UsernameValidator() 

  upload(StringValidator.LengthBetween(6, 15));

upload(new PatternValidator("[a-z0-9_-]+"));

  

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Question 10. How To Create A Password Field In Apache-wicket?

Answer :

create a password field

final PasswordTextField password = new PasswordTextField("password", Model.Of(""));

//for homes file

password.SetLabel(Model.Of("Password")); 

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Question eleven. How To Create A Textarea In Apache-wicket?

Answer :

//create a textarea subject for deal with

final TextArea<String> cope with = new TextArea<String>("cope with",Model.Of(""));

cope with.SetRequired(real);

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Question 12. How To Create Checkbox In Apache-wicket?

Answer :

final CheckBox chk0 = new CheckBox("checkbox0", Model.Of(Boolean.TRUE));

 final CheckBox chk1 = new CheckBox("checkbox1",

new PropertyModel<Boolean>(this, "checkbox1"));

very last CheckBox chk2 = new CheckBox("checkbox2",

new PropertyModel<Boolean>(this, "checkbox2"));

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Question 13. How To Create Multiple Checkboxes In Apache-wicket?

Answer :

non-public static very last List<String> LANGUAGES = Arrays.AsList(new String[] "Java", ".NET", "PHP", "Python", "C/C++" );

// preserve the checkbox values

non-public ArrayList<String> languagesSelect = new ArrayList<String>();

very last CheckBoxMultipleChoice<String> listLanguages = new CheckBoxMultipleChoice<String>("languages", new Model(languagesSelect), LANGUAGES);

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Question 14. How To Create Radio Button In Apache-wicket?

Answer :

//choices in radio button

personal static very last List<String> TYPES = Arrays.AsList(new String[]  "Shared Host", "VPN", "Dedicated Server" );

RadioChoice<String> hostingType = new RadioChoice<String>("website hosting", new PropertyModel<String>(this, "selected"), TYPES);

Question 15. How To Create Single Selected Listbox?

Answer :

// unmarried list choice

private static final List<String> FRUITS = Arrays.AsList(new String[]  "Apple", "Orange", "Banana" );

ListChoice<String> listFruits = new ListChoice<String>("fruit", new PropertyModel<String>(this, "selectedFruit"), FRUITS);

 listFruits.SetMaxRows(5);

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Question 16. How To Create Multiple Selected Listbox In Apache-wicket?

Answer :

//alternatives in list box

private static very last List<String> NUMBERS = Arrays.AsList(new String[] "Number 1", "Number 2", "Number three", "Number four", "Number five", "Number 6" );

//variable to keep the chosen more than one values from listbox, 

//and make "Number 6" decided on as default fee

private ArrayList<String> selectedNumber = new ArrayList<String>(

Arrays.AsList(new String[]  "Number 6" ));

 ListMultipleChoice<String> listNumbers = new ListMultipleChoice<String>(

"range", new Model(selectedNumber), NUMBERS);

 //HTML for more than one pick out listbox

<select wicket:id="number"></select>

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Question 17. How To Create Dropdown Choice In Apache-wicket?

Answer :

//Java 

import org.Apache.Wicket.Markup.Html.Shape.DropDownChoice;

//selections in dropdown field

private static final List<String> SEARCH_ENGINES = Arrays.AsList(new String[] 

"Google", "Bing", "Baidu" );

 //variable to maintain the chosen value from dropdown field,

//and also make "Google" is selected by default

private String decided on = "Google";

 DropDownChoice<String> listSites = new DropDownChoice<String>(

"websites", new PropertyModel<String>(this, "selected"), SEARCH_ENGINES);

 //HTML for dropdown field

<select wicket:id="sites"></select>

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Question 18. How To Create Fileupload Field In Apache-wicket?

Answer :

//Java

import org.Apache.Wicket.Markup.Html.Form.Upload.FileUploadField;

 form.SetMultiPart(genuine);

form.Upload(fileUpload = new FileUploadField("fileUpload"));

 //HTML

<input wicket:id="fileUpload" type="file"/>

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Question 19. How To Create Select Option As Menu Wise In Apache-wicket?

Answer :

//Java 

import org.Apache.Wicket.Extensions.Markup.Html.Form.Choose.Select;

import org.Apache.Wicket.Extensions.Markup.Html.Shape.Select.SelectOption;

        //variable to preserve the selected cost from dropdown field,

        //and additionally make "jQuery" decided on by using default

        personal String decided on = "jQuery";

  Select languages = new Select("languages", new PropertyModel<String>(this, "selected"));

shape.Upload(languages);

languages.Upload(new SelectOption<String>("framework1", new Model<String>("Wicket")));

languages.Add(new SelectOption<String>("framework2", new Model<String>("Spring MVC")));

languages.Add(new SelectOption<String>("framework3", new Model<String>("JSF 2.Zero")));

languages.Upload(new SelectOption<String>("Script1", new Model<String>("jQuery")));

languages.Add(new SelectOption<String>("Script2", new Model<String>("prototype")));

 //HTML for dropdown box

<select wicket:id="languages">

<optgroup label="Frameworks">

<option wicket:id="framework1" >Wicket (1.4.7)</option>

<option wicket:id="framework2" >Spring MVC (three.0)</option>

<option wicket:id="framework3" >JSF (2.Zero)</option>

</optgroup>

<optgroup label="JavaScript">

<option wicket:id="Script1" >jQuery (1.6.1)</option>

<option wicket:id="Script2" >prototype (1.7)</option>

</optgroup>

</select>

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Question 20. What Is Pallet Component In Apache-wicket?

Answer :

Wicket extension comes with a special “Palette” component, which render two pick boxes, and allow user to transport gadgets from one pick field into every other.

//Java

import org.Apache.Wicket.Extensions.Markup.Html.Shape.Palette.Palette;

 very last Palette<Hosting> palette = new Palette<Hosting>("palette",

new ListModel<Hosting>(selected),

new CollectionModel<Hosting>(listHosting),

renderer, 10, true);

  //HTML

<span wicket:id="palette"></span>

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Question 21. How To Create Custom Validator In Apache-wicket?

Answer :

See precis steps to create a custom validator :

1. Implements IValidator.

Import org.Apache.Wicket.Validation.IValidator;

 public elegance Strong PasswordValidator implements IValidator<String>

...

2. Override validate(IValidatable validatable).

Public magnificence StrongPasswordValidator implements IValidator<String>

...

@Override

public void validate(IValidatable<String> validatable) 

  //get input from attached component

final String area = validatable.GetValue();

  

3. Attached custom validator to shape aspect.

Public class CustomValidatorPage extends WebPage 

  public CustomValidatorPage(final PageParameters parameters) 

       final PasswordTextField password = new PasswordTextField("password",Model.Of(""));

//connected custom validator to password subject

password.Upload(new StrongPasswordValidator());

  //...

 

Question 22. How To Integrate Apache-wicket With Spring?

Answer :

Override Wicket application init() method with this “addComponentInstantiationListener(new SpringComponentInjector(this));“.

File : Wicket software magnificence

bundle com.Withoutbook;

 import org.Apache.Wicket.Protocol.Http.WebApplication;

import org.Apache.Wicket.Spring.Injection.Annot.SpringComponentInjector;

import com.Withoutbook.Consumer.SimplePage;

 public class WicketApplication extends WebApplication 

  @Override

public Class<SimplePage> getHomePage() 

  return SimplePage.Magnificence; // return default page

  @Override

protected void init() 

  excellent.Init();

addComponentInstantiationListener(new SpringComponentInjector(this));

  

 

Now, you may inject Spring bean into Wicket thing thru @SpringBean.

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Question 23. How To Get Servletcontext In Apache-wicket Application?

Answer :

Yes, you could get the ServletContext elegance via Wicket’s WebApplication magnificence like this :

import javax.Servlet.ServletContext;

import org.Apache.Wicket.Page;

import org.Apache.Wicket.Protocol.Http.WebApplication;

import com.Withoutbook.Good day.Hello;

 public class CustomApplication extends WebApplication 

  @Override

public Class<? Extends Page> getHomePage() 

  ServletContext servletContext = WebApplication.Get().GetServletContext();

go back Hello.Class; //return default web page

  

 

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Question 24. How To Keep File Validation In Apache-wicket If No File Has Been Selected?

Answer :

To restore it, simply override the validateOnNullValue() method like this :

FileUploadField fileUpload = new FileUploadField("fileupload",new Model<FileUpload>());

 fileUpload .Upload(new AbstractValidator()  

        public boolean validateOnNullValue()

        return actual;

  blanketed void onValidate(IValidatable validatable)  

FileUpload fileUpload = (FileUpload) validatable.GetValue();

     covered String resourceKey() 

    return "yourErrorKey";

 );

Now, when no file is chosen, and publish button is clicked, validation can be executed.

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Question 25. How To Create 404 Error Page?

Answer :

<filter-mapping>

<filter-name>wicket.WicketTest</filter-name>

<url-pattern>/*</url-pattern>

<dispatcher>REQUEST</dispatcher>

<dispatcher>ERROR</dispatcher>

</filter-mapping>

<error-page>

<error-code>404</error-code>

<location>/error404</location>

</error-page>

public elegance WicketApplication extends WebApplication 

  @Override

protected void init() 

  mount(new QueryStringUrlCodingStrategy("error404",ErrorPage404.Magnificence));

  

 

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