Now, as you have the latest-stub-articles xml from Wikipedia, it's time to test the two XML parsers in java to see which is faster, and why.

Use the DOMParser to parse the xml file and get a Document instance.
Do not go through all the nodelists and nodes, just obtain the Document instance from the parse method.
Notice the ammount of time needed for the DocumentBuilder to parse your file.

Use the SAXParser to parse the xml file. Extend DefaultHandler, and see the time needed.

In order to measure the time needed for an operation to complete in java, check out the System.currentTimeMillis() : )

As the file format above is something like:

  <page>
    <title>Translations:Wikimedia Foundation elections/FDC Ombudsperson elections/2013/13/en</title>
    <ns>1198</ns>
    <id>2239772</id>
    <revision>
      <id>5552639</id>
      <parentid>5394284</parentid>
      <timestamp>2013-06-09T12:36:44Z</timestamp>
      <contributor>
        <username>FuzzyBot</username>
        <id>1058846</id>
      </contributor>
      <comment>Importing a new version from external source</comment>
      <text id="5538008" bytes="520" />
      <sha1>lwdr5q15u1n9bsxgipym50earq8tpd8</sha1>
      <model>wikitext</model>
      <format>text/x-wiki</format>
    </revision>
  </page>

I'd like you to print the username of the wikipedia contributor, that has contributed the most! Choose between the two major parsers and use one of them. Use and combine the startElement, endElement, and characters methods in your extension of DefaultHandler (if you are using SAXParser, or use XPath or XQuery + Document if you prefer and like the DOMParser more (for some reason).

Friendly advice: If you haven't use the DOM Parser in Java, don't use it here. You won't like it. It is slow, as it builds up the whole tree. You don't need that. Also, XPath and XQuery are not as easy as they seem.

Create a class CoreJavaCourse with fields

List<Student> enrolledStudents
int courseId
String courseName

A Student class has the following:

int studentId
String name

Now: 0) in a main method: Create an instance of the CoreJavaCourse class.

1. Create a JAXBContext of this class and the class Student.
2. Obtain a Marshaller from the JAXBContext instance.
3. Marshal the CoreJavaCourse instance.
4. Verify that you have correct xml output to the console.

4.5) Create an Unmarshaller from the JAXBContext instance.
5) Unmarshal the file to an instance.
6) Override the toString() method and print it to the console, verifying that you have unmarshalled the xml file properly.

7. Now, let's switch the whole procedure to JSON! We will reuse are @XML bindings, but we will just produce JSON
8. First, download and link the jettison library
9. Create a MappedNamespaceConvention instance.
10. Create an instance of MappedXMLStreamWriter instance using the MappedNamespaceConvention instance you just created.
11. On your Marshaller instance, call the marshal method, but giving it the MappedXMLStreamWriter instance you just created. This instance will apply the conversion from XML to JSON, so be sure you pass your MappedXMLStreamWriter argument!
12. Now, you can go and check the file you've just marshalled to (or the console, if you've marshalled to the console). You see the output is JSON.
13. Repeat the procedure, but for unmarshalling, this time using a MappedXMLStreamReader instance. See if you can work your way without looking at the resources.

If somewhere along the process you get lost, check out the materials.md file provided. Be wary - the contents there are basically everything you need and you will learn nothing if you just head there and copy-paste some code. Don't do that. Try to understand the whole process, what is happening and why.