How does one write a JSP page?

You can use Oracle JDeveloper to create JSP pages. Alternatively you can open a standard text file and code the required HTML and Java manually. Look at this example:

<HTML>
<BODY>
<% out.println("Hello World"); %> 
Today is: <%= new java.util.Date() %> 
Page generated with: <%= this.getServeleteInfo() %>