For this assignment, you will create a simple Jetty web server that allows users enter a URL, and view the HTTP headers for that URL.

Before starting this assignment, you should install Jetty and servlets as a third-party libraries in Eclipse.

You must do the following for this assignment:

1. HeaderServer.main(): Start a Jetty web server on port 8080, and map /check to the HeaderServlet servlet.

2. HeaderServer.HeaderServlet.doGet() This servlet should display a simple web form that allows users to enter a link, and press a button to display the HTTP headers for that link.

If the appropriate link parameter is present in the GET request, the servlet should also fetch and display the HTTP headers for the provided link. If the servlet is unable to fetch the headers, display a message on the web page instead. You can use HTTPFetcher to get the headers, and display the resulting text in a pre block.

Below is one example for how this assignment might look. You can use any of the servlet code provided as a starting point.

You can earn 5 points extra credit on this homework assignment by doing both of the following:

1. Show header fields in a table instead of a single block of text. (1 point)

2. Use Bootstrap 3.x to create a responsive mobile-ready website. (2 points)

3. Your HTML code must pass the W3C HTML Validator. (2 points)

The examples shown below implement the extra credit features.

The following is one example implementation of this assignment. The exact appearance does not need to match this.

When a valid link is provided, the resulting web page might look as follows:

When an invalid link is provided, the resulting web page might look as follows:

Note this is just an example. It is using Bootstrap 3.x and parsing the header fields, but neither of these are requirements for this homework assignment.

There are no unit tests for this homework assignment. It will be graded manually.