Problem 2
State whether each of the following statements is true or false. If false, explain why. a) An Httpservlet's calls method doGet upon receiving a get request and method doPost upon receiving a post request. (true/false). b) A User-Agent header contains information about the server. (true/false). c) DocumentBuilder's static method newDocumentBuildex creates a new DocumentBu11dex. (true/false). d) In this case study, TipTestservlet uses XSLT to transform XML Tip Test Documents to well formed content for all clients. (true/false). e) The J2ME CLDC package consist of java. Ío, Java. lang and java.net. (true/ false). f) The application management software loads a MIDlet on a MIDP device. (true/false). g) The application description file specifies such information as the MIDP device's configuration and the MIDlet's name. (true/false). h) Classes Alert, Form, Screen, and List are the concrete classes of the MIDP highlevel user-interface package, (true/false). i) A javax.microedition. 1 cdu1. Command object encapsulates an action to be executed by the object that received the Command. (true/false). j) An HttpSession's Set-Cookie header field contains session information. (truc/ false).
Problem 3
To make TIpTestservlet more manageable and extendable, we stored the database driver name and URL in the \(\langle\text { init -param }>\text { element in web. } x \text { and } . \text { List } 3\) other constants that we could have stored from Welcomeservlet and TipTestservlet in the \(\langle\) init-param> element.
Problem 5
Method getResult Table of TipTestservlet creates a two-dimensional Stringarray Resultset representation. However, because these dimensions are pre-defined (seven rows by five columns), the string array cannot store additional rows if we append another tip to the database. Modify TipTestservlet so that it can handle any number of tips from the database. Use techniques shown in Chapter \(8,\) Java Database Connectivity \((\mathrm{JDBC}),\) to create a scrollable Resultset so that you can determine the number of rows in the Resultset and size the string array accordingly.
Problem 6
Lines \(29-38\) of class TipTestMIDIet specify the servlet URL and the Welcomeserv1et URL. This approach can be problematic if a network administrator changes either URL. In practice, we would like the application descriptor file to contain the servlet URL and the MIDP-device user to specify the WelcomeServlet URL with the MIDP-device keypad. a) Encode the servlet URL - http: / / 10calhost : 8080/advjhtp1/-in the TipTestMIDIet application descriptor file by typing Servlet-URL : http: / / localhost : 8080 /advjhtp1/ at the end of TipTestMIDlet's . jad file. In TipTestMIDlet, use method get AppProperty of class MIDlet to return the servlet URL. (Method getAppProperty takes a property-tag string-e.g., "Servlet-URL"-as an argument and returns the string associated with that property.) b) Enable the user to specify the we1comeservlet URL. Modify the class TipTest- MIDIet constructor to create mainscreen (line 51 ) as a TextBox -a Screen subclass that enables the user to input text. A rext Box constructor takes four arguments: 1) a string that represents the TextBox's title; 2 ) a string that represents the TextBox's initial contents; 3 ) an int that represents the maximum number of characters allowed in the TextBox; 4 ) an input constraint int that specifies the required input format-e.g., if you want the user to enter a phone number, the constraint is TextField .PHONENUMBER. We want the user to enter a URL, so the constraint is TextField. URL. Use method getstring of class TextBox to return the TextBox's contents (user input) to store the We1comeServlet URL when the user presses the Select soft button.
