NoClassDefFoundError Htmlunit

I'm new to HtmlUnit. I tried a simple code for loading a web page using htmlunit and use the xpath to get to a specific div tag. The xpath is correct. I have verified using the console.

The code that so far I tried is

import java.util.List;

import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlElement;
import com.gargoylesoftware.htmlunit.html.HtmlPage;

public class Test {

public static void main(String s[]) throws Exception 
{
    WebClient client = new WebClient();
    HtmlPage page = client.getPage("http://jpu1.pv.sv.nextag.com/serv/iinedan/buyer/outPdir.jsp?search=camera");

    List<?> items = page.getByXPath("//div[contains(@class,'search-result-cards')]//div[contains(@class,'listContainer')]");

    for(HtmlElement item : (List<HtmlElement>)items)
    {
        List<?> imageContainer;

        imageContainer = item.getByXPath("//div[contains(@class,'imageContainer')]/a");

        System.out.println("Image container data length : "+imageContainer.size());

        System.out.println("Image "+imageContainer.toString());

    }

  }

}

But when I execute this code, I'm facing the following exceptions.

Exception in thread "main" java.lang.NoClassDefFoundError: org/w3c/dom/ElementTraversal
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at Test.main(Test.java:11)
Caused by: java.lang.ClassNotFoundException: 
org.w3c.dom.ElementTraversal
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 37 more

It seems to like its a configuration isssue. I downloaded the jar from the site and added it to my refrenced library. IDE that I'm using is eclipse. HtmlUnit version is htmlunit-2.13.jar

Solution

The org/w3c/dom/ElementTraversal present in library xml-apis-1.4.01.jar on which htmlunit depends on. So, as a solution you need to put this jar in your project's classpath.

However, htmlunit depends on number of libraries. And it could happen that, after you resolved the current error, you will get a noClassDefFoundError for some other class.

In order to resolve it easily, start using Maven.

Create a maven project.

Add an entry for htmlunit dependency in pom.xml as follows :

<dependencies>
<dependency>
    <groupId>net.sourceforge.htmlunit</groupId>
    <artifactId>htmlunit</artifactId>
    <version>2.13</version>
</dependency>
</dependencies>

Now create a new class and add your code there.

Maven will ensure, all transitive dependencies of any library to be available and keep those in project classpath automatically (if in IDE).