Fast Answers to Frequently-Asked Questions

• Question 1 : Where can I find the Home Page for ENCE 200?
• Question 2 : How do I get a GLUE computer account?
• Question 3 : How do I activate a GLUE printing account?
• Question 4 : How can I dial into the University from Home?
• Question 5 : What WWW browsers are available at UMCP?
• Question 6 : I want to save a WWW page -- What's the difference between txt, html and postcript?
• Question 7 : How do I send a WWW page to the printer?
• Question 8 : What editors are available for file creation?
• Question 9 : How do I compile and run a small C program?
• Question 10 : Will a computer program compiled on a SUN workstation also run on a PC?
• Question 11 : Where should I put my Home Page?
• Question 12 : How can I get started with my Home Page?
• Question 13 : What content will I need to include on my Home Page?
• Question 14 : I'm on an IBM PC machine...how do I use the FTP program?
• Question 15 : From where can I download ftp and terminal emulator software?
• Question 16 : Where can I find a selection of background patterns?
• Question 17 : How can I download a background pattern from someone's page?
• Question 18 : How can I put a counter on my home page?
• Question 19 : I can't send E-mail from my Netscape Browser. What's the problem?
• Question 20 : How do I get an Internet domain name for my new company?
• Question 21 : What is a script file? How do I create one?
• Question 22 : What colors can I use English names for in HTML?
• Question 23 : From where can I download NetTerm?
• Question 24 : How do I make acrobat pdf files?
• Question 25 : What info do I need to access WebCT?
• Question 26 : How do I forward wam account e-mail to my glue account?

New Faq ... (Work in Progress)

• I am at school -- how do I send a file to the printer?
• What is a tar file? How do I work with them?
• What is a zip file? How do I create one?

• Question 1 : What are some of the key differences between C and Java?
• Question 2 : How has Java changed from versions 1.0 through 1.5?
• Question 3 : What editions of Java exist?
• Question 4 : How do I access the java compilers on the glue and wam systems?
• Question 5 : How do I use the just-in-time compiler?
• Question 6 : What is the Java Runtime Environment (JRE)?
• Question 7 : What are the basic data types supported in Java?
• Question 8 : How do the keyword modifiers work in Java?
• Question 9 : What is a Java package?
• Question 10 : What are the Java packages I will most likely use in this course?
• Question 11 : What are the Java Foundation Classes (JFC)?
• Question 12 : What is the relationship between AWT, Swing and the JFCs?
• Question 13 : Why should I upgrade my Java graphics from AWT to Swing?
• Question 14 : Are the AWT and Swing components designed to work together?
• Question 15 : What is the model-view-controller (MVC) architecture?
• Question 16 : How does the MVC architecure work in Swing?
• Question 17 : What is a JAR file and how do I use them?
• Question 18 : What is a JavaBean?
• Question 19 : How can I run an applet?

New Faq ... (Work in Progress)

• What is an Integrated Development Environment (IDE)?
• Where can I find Eclipse and Netbeans (IDEs for Java Development)?
• How do Eclipse and NetBeans compare?
• Where in my account should I put my Java source code files?
• How to I create the Java source code file?
• What is the difference between Java source code and Java bytecode?
• What is a jar file? How do I work with them?
• Where can I find the latest version of Java?
• What programs will I find in the Java Development Kit (JDK)?

Question 1 : Where can I find the Home Page for ENCE 200?

Answer : Move the cursor to the location bar on your browser and enter
         the URL:

         http://www.isr.umd.edu/~austin/ence200.html

Question 2 : How do I get a GLUE computer account?

Answer : All Students in ENCE 200 will be expected to have a GLUE (or WAM)
         computer account. To activate your account, go to Rm 1400 in the
         Computer Science Services (CSS) building ... and follow the signs.

         For more info, see:

         http://www.helpdesk.umd.edu/faqs/unix

Question 3 : How do I activate a GLUE printing account?

    The Glue system operates under a "Pay-for-Print" policy.

    To print from a open glue lab, you will need a print account. This 
    account can be used not only for the Glue Open labs, but also all over 
    campus (WAM labs: PG2, Hornbake...). 

    Each page costs $0.10. Users must obtain a Terrapin Express card in
    Room 1109 South Campus Dining Hall, in the hours 08:00 - 16:00.
    After doing this, they must get their print account activated in the
    Laser Print Cost Recovery (LPCR) office, Room 3326 Computer Science
    Center. The minimum deposit for the Terrapin Express Account is $25. 

    Users can check their print account by telnetting to the address: 

          bank.umd.edu 

    The login id is "teller". The bank will then ask for the print account 
    number and the password. The user can then move funds from the Terrapin 
    Express account to the print account. 

    For further help, please consult the first-aider on duty.

Question 4 : How can I dial into the University computers from Home ?

Answer : You can't. Dial-up access to the College of Engineering's network
         of UNIX servers was discontinued in May 2007.

         Sol'n. Access to school is provided through Verizon/Comcast.

Question 5 : What WWW browsers are available at UMCP?

Answer: The glue system currently supports Netscape 7 and the UNIX
        version of Microsoft IE 6/7. 

        Many of your will now have browsers on your laptops ... my 
        personal preference is Netscape 7 on Windows/PC platforms
        and "Safari" on Apple Powerbook running Mac OS X.

Question 6 : I want to save a WWW page. What's the difference between txt, html and postcript ?

Answer : To save a file, click on the "File" item located in the top
         left-hand corner of the Netscape Browser.

         Then select the pull-down menu item that has a title

             "Save As..."

         A small window should pop-up requesting information on the
         location and format for the file containing the saved page.
         The three file formats are:

         Text       -- Save the the text within the page.

         Source     -- Save the html code for the page, including the text,
                       tags etc..

         Postscript -- This saves the file in Postscript format.
                       Postscript is a special computer language understood
                       by many printers, and is used to send text and graphics
                       of all varieties to the printer.  You can use this
                       option to save an image of a web page as a Postscript
                       file, which can then be sent to a Postscript printer to
                       reproduce the file on paper. 

Question 7 : How do I send a WWW page to the printer?

Answer : The answer to this question will depend on the local configuration
         of your computer. Generally speaking you will need to give a command
         like

              qpr -q name-of-printer name-of-postscript-file.ps

         See the lab attendant for specific details.

         Note. Before this command will work, you will need to get a 
         print account....

Question 8 : What editors are available for file creation?

Answer : "vi" and "pico". A summary of basic vi commands is located in the
         appendix to the class notes. For more information on vi, follow
         the links to Online Computer Documentation at Berkeley.

Question 9 : How do I compile and run a small C program?

Answer : Chapter 3 of Austin/Chancogne contains step-by-step instructions
         for compiling small C programs using the Gnu C compiler.
         Pay particular attention to command line arguments needed to
         set the filename for the program executable, and to link the
         program object code to the math library. 

Question 10 : Will a computer program compiled on a SUN workstation also run on a PC?

Answer : No.

Question 11 : Where should I put my home page?

Answer : When you log into your Glue account, you are initially
         in your home directory.  Typing:

           cd ../pub

         put you in your public directory.  This is a
         directory that the general public has access to, and
         therefore this is where your home page should be stored.

         You should put your home page in a file

            Welcome.html
         
         located inside the pub directory. So if your login
         name is let's say "dubya", then the location of your
         home page will be something like

            /afs/ ... /dubya/pub/Welcome.html

         (The row of dots indicates that the file system will change from
         machine to machine) Folks from outside the University of Maryland
         will be able to view your home page using the URL

            http://www.glue.umd.edu/~dubya/

         More Information : Follow the link to "Instructions for
         Creating a Personal Home Page" from the Internet Resources
         section of the ENCE 489C home page.

Question 12 : How can I get started with my Home Page?

Answer : You will need to write your Home Page in the Hypertext Markup
         Language (HTML). An easy-to-read introduction to HTML is

         "A Beginners Guide to HTML,"  

         located in section two of the Class Notes.

Question 13 : What content will I need to include on my Home Page?

Answer : Here is a list of required and optional content for your home
         page.

         Required Content
         ================

         * Images of yourself (...or something similar ....).
         * A resume, containing career objective, educational background,
           (including schools attended), work experience, and a summary
           of your computer skills -- hey, you can list HTML as one of
           your Web skills.
         * A summary of classes taken at University of Maryland.
         * An e-mail link to your computer account.
         * Signposts that help a visitor navigate the layout of pages
           in your public_html directory -- one way of doing this is
           to add an index page to your home page.
         * Somewhere on your page, you should use a <table> tag.

         Where appropriate, your page should contain hypertext links to
         schools, places of of employment etc ....

         Also, because the purpose of your page is for self promotion, the
         page layout should tidy and "visually appealing."  Learn how to
         create tables in html, and how to create pages with a good balance
         of "hot" and "cold" colors.

         Optional Content
         ================

         * Links to school projects presented in an html format.
         * Information on your hobbies, country of origin, sports, musical,
           political interests etc .....
         * Links to interesting things on the Internet, such as search
           engines, tools for WWW development, Java applets .....

Question 14 : I'm on an IBM PC machine...how do I use the FTP program?

Answer : The File Transfer Protocol (FTP) program works on the same
         concept as the file manager as in Windows 3.1.

         To transfer files:

      1. Save the file onto disk.  Hard or floppy.

      2. Click on the window icon FTP.  This icon is usually pink letters
         on a white background. This icon will open up the "File Transfer
         Protocol" program.

      3. Click on the space that says profile name.  You will want to be
         able to get into glue with your login and password.
         One of the set ups in the drop list will allow you to do this.

      4. Fill in your login where it says user id and password where it
         asks.

      5. Click on OK

      6. You will now see a split window.  on the left hand side is the
         computer you are on, and on the right is your computer account.
         In order for you to put stuff(files, etc.) into your pub account
         you have to open up that part of your account.  Look at the right
         part of the screen.  In the upper right you will see something
         that looks like   ..  Click on the two dots.  This will take you
         up a level in your account.

      7. Now you should see another list of things. One should be pub.
         This is you pub account. Click on pub.  If you have started your
         web site you should at least see Welcome.html here.
         You are now in the pub part ofyour account.

      8. To transfer things there you now must look at the upper left of
         the window.

         Here you will see things that resemble the computer you are on.
         For instance [-a-], [-c-], are both drives.  [-a-] is your floppy
         drive and [-c-] is your hard drive.  If you have things saved on a
         floppy click on [-a-] and then you will see all the files that are
         on your disk.

      9. Now highlight the thing you want to transfer by clicking on it.

     10. Now that it is highlighted click on the right arrow and the
         program will transfer that file to your school account.

     11. Your done.  The file should now be on the right side bottom.  If it
         is there, then it is in your pub account.

Question 15 : From where can I download "ftp" and "terminal emulator" software?

Answer : 30 day trial copies of file transfer programs (ftp) and
         "terminal emulator" software can be downloaded from:

                http:www.download.com
         and
                http:www.tucows.com

         Note. In August 2005, the university upgraded its networks
         so that all communication from outside sources is now
         encrypted. This feature makes it much more difficult for
         hackers to break into the university networks.

         Before August 2005, I used CRT terminal emulator and
         bulletproof ftp program to access the computer systems
         as school and transfer files back and forth between home
         and school. Unforunately, these no longer work.

         All terminal emulators and file transfer programs (ftp)
         must now use secue shell (ssh).

         It you want to download a ssh client to your windows machine,
         The office of information technology (OIT) recommends TeraTerm,

         See  http://www.helpdesk.umd.edu/topics/applications/terminal/ .

         which is ssh (secure shell) for Windows.

         OIT has also created a new service SSH Gateway on the Web.
         Go to:  href="http://www.helpdesk.umd.edu/documents/4/4576/ 

         At home I use TurboFTP to transfer files/directories to/from school.
         TurboFTP has a very friendly graphical user interface
         that shows both the windows and unix files systems.

         You can download a trial version from http://www.tucows.com.

Question 16 : Where can I find a selection of background patterns?

Answer : A good starting point is:

         http://home.netscape.com/assist/net_sites/bg/backgrounds.html

         For more sites, go to a search engine and do a search on
         "background pattern"

Question 17 : How can I download a background pattern from someone's page?

Answer : If you are running netscape on a PC, then you can simply move the
         cursor to the background, and click on the right button. A small
         window will appear asking where you want the background image to
         be saved.

         Otherwise, you can retrieve a background color pattern directly
         from the Netscape cache (the cache stores images and patterns
         locally on your computer, thereby enhancing performance).

         The cache can be accessed by typing

         about:cache

         in the "Location" window of Netscape.

Question 18 : How can I put a counter on my home page?

Answer : Free counters are available at:

         http://counters.qpt.com/

Question 19 : I can't send E-mail from my Netscape Browser. What's the problem?

Answer : First, check your html code to make sure you haven't made a
         silly typo. The html should look something like:

         E-mail : <a href="mailto:your-login-name@glue.umd.edu"><b>
                                  your-login-name@glue.umd.edu </b></a>

         If your E-mail still doesn't work then perhaps
         your Netscape browser settings are incorrect.

         To check your mail preferences go to the Netscape Options
         menu and button on "Mail and News Preferences". Then select
         the services page. The SMTP (simple main transfer protocol)
         setting for outgoing mail should be

             smtp.glue.umd.edu

         for glue users, and 
         
             smtp.isr.umd.edu

         for users at ISR.

Question 20 : How do I get a domain name for my new company?

Answer : You can register a domain name for your company by contacting
         Network Solutions Inc. See

              www.internic.net.

         I believe the fee is $100/yr.

         Nothing happens physically? All this means is that some nameserver
         in the Internet world will contain an entry for your domain and
         point it to some IP address. If there is a machine on the Internet
         with that IP address, then all packets will be forwarded there.
         Otherwise, nothing will happen.

         Do I need to purchase a server and have it on for 24 hours/day?

         No. There are several companies out there that can house your
         domain for you for a fee. However, you are free to do so if you
         wish. 

         For more information, see the internic web site

         www.internic.net

         and the FAQ at

         http://rs.internic.net/domain-info/registration-FAQ.html

Question 21 : What is a script file? How do I create one?

Answer : A script file contains a copy of all of the commands
         given at the keyboard and all of the output sent to 
         the computer screen.

         The syntax for starting a script file is:

             prompt >> script name-of-script-file

             ..... now go ahead and run your programs. A copy
                   of the commands and program output will be
                   echoed to file "name-of-script-file"
         
         The script file is terminated by typing

             prompt >> exit

         Now send the "name-of-script-file" file to the printer.

Question 22 : What colors can I use English names for in HTML?

Question 23 : From where can I download NetTerm?

Answer : Try ......

         http://www.netterm.com/html/downloads.html

Question 24 : How do I make acrobat pdf files?

Answer: The isr has a daemon running that automtically makes pdf
        files. To use it, you log into an isr machine, and ftp the
        postscript file that you wish to convert to your account.
        Then copy the file to the directory

         /software/isrwww/html/misc/tools/acrobat/IN

         Wait for a few minutes, and the postscript file that you
         copied should appear along with a pdf file in the directory

         /software/isrwww/html/misc/tools/acrobat/OUT

         Move the pdf file and the postscript file out of the OUT
         directory to the place in your own homespace where you want
         to put them.

Question 25 : What info do I need to access WebCT?

    The Web Courses Tool (WebCT) at Maryland operates as a secure
    web server. The web address is:

        https://www.courses.umd.edu/

    Students use their SID number and their MARS logon password
    to get onto the page.

Question 26 : How do I forward wam account e-mail to my glue account?

Answer : Log into your wam account and create a file called
         .forward that contains the line
 
             loginname@glue.umd.edu

         Of course, you should put your "loginname" here ...

Question 1 : What are some of the key differences between C and Java?

    No preprocessor  -- Java does not include a preprocessor
    and does not define any analog of C's #define, #include, and so
    forth.  Program constants are replaced with

       static final data_type = data_value;

    for example,

       static final double dPi = 3.1415926;

    No global variables  -- Java defines a very clean namespace.
    Packages contain classes, classes contain fields and methods, and
    methods contain local variables.

    Well-defined primitive type sizes  -- Unlike C, all of
    the primitive datatypes in Java have well-defined sizes.

    No pointers  -- Java classes and arrays are reference types
    and references to objects and arrays are akin to pointers in C.
    However, in Java there is no address operator or mechanism to
    increment or decrement a pointer (i.e., do pointer arithmetic).

    Garbage collection  -- The Java virtual machine performs
    garbage collmection so that Java programmers do not have to
    explicitly manage (e.g., release memory to the operating systems)
    memory used by all objects and arrays.

    Method overloading  -- Java programmers can define multiple
    methods with the same name, so long as the methods have different
    parameter lists.

    Variable declarations anywhere  -- C requires local variable
    declarations to be made at the beginning of a method or block.
    Java allows them anywhere in the method or block.

    For more information, see the Nutshell book (2000).

Question 2 : How has Java changed from versions 1.0 through 1.5?

Answer : During the past twelve years (1996-2007) six versions of
         Java have been released. The key features in each release
         are as follows:

         Java 1.0  -- The first public release of Java contained 212
         classes organized into 8 packages.

         Java 1.1  -- The second release doubled the size of the Java
         platform to 504 classes organized into 23 packages.

         This release introduced the delegation event handling model
         and inner classes, leading to significant improvements in
         performance of the Java virtual machine.

         Java 1.2  -- The third release tripled the size of Java to
         1520 classes organized into 59 packages.

         This release is also called the Java 2 Platform.

         Java 1.3  -- Minor updates to Java 1.2 release (e.g., includes
         support for Java Sound as part of the Java Platform).

         Java 1.4  -- The major release increased the number of
         classes to 2,991 classes and interfaces located in 135
         packages.

         For ENCE 200, Java 1.4 brings with it builtin support for handling
         XML.

         Java 1.5  -- The release occured early in 2005. The
         most notable improvement for ENCE 200 is improved support for
         formatted output using C's printf() functionality.

         Experienced C programmers will see that a lot of the nice 
         features in C are now also available in Java 1.5 (e.g., variable
         argument lists; enumerated data types).

         Java 1.6  -- Released in early 2007.

Note. Both the glue and wam systems now support Java 1.5. You may also download Java 1.5 or 1.6 to your desktop computer/laptop from java.sun.com.

Note. The Mac OS X operating system -- Tiger and Leopard Editions -- comes with Java 1.5 already installed.

Question 3 : What editions of Java exist?

Answer : SUN is working to create different versions of the Java platform
         for different uses. In this class we will use:

         -- The Standard Edition (details shown in previous question).

         Several versions are in development:

         -- Java 2 Enterprise Edition (J2EE) for Enterprise developers of
            the Java Platform.

         -- Micro Edition for consumer electronics, handheld PDAs and 
            cellular telephones.

Question 4 : How do I access the Java compilers on the glue and wam systems?

Answer : To access the Java 1.5 compiler on the glue/wam system
         simply type:

         >> tap java

         You can check the version of Java with the command:

         >> java -version

         As of January 2006, Java 1.5 is the default compiler ...

         Then you can compile a small java program by simply typing
         something like:

         >> javac SmallProgram.java

         The Java 1.4 compiler is available for download from java.sun.com.

Question 5 : How do I use the just-in-time compiler?

Answer : One problem with Java bytecodes is their slow execution
         by Java virtual machines. A promising advance is just-in-
         time compilation, where Java bytecodes are converted 
         on-the-fly into native-platform machine code (see, for
         example, SUN's hotspot technology).

         Add details on compilation ....

Question 6 : What is the Java Runtime Environment (JRE)?

Answer : The Java Runtime Environment contains everything needed to run a
         Java program, but does not software needed to compile Java source
         code.

         One version of the JRE is implemented as a Java-plug in, designed
         to be connected to Netscape and Microsoft IE browsers.

Question 7 : What are the basic data types supported in Java?

The Java language has eight basic data types:

Question 8 : How do the keyword modifiers work in Java?

Answer : Java uses keyword modifiers to adjust the scope and storage
         of program elements in much the same way as C.

         However, the details of implementation are quite different...
         as shown the the table.

Question 9 : What is a Java package?

Answer : A Java package is a named collection of classes (and possibly
         sub-packages.

         Packages allow for the grouping of related classes and the
         definition of a namespace for the classes they contain.

Question 10 : What are the Java packages I will most likely use in this course?

We will use packages associated with Java language, utilities and networking (e.g., downloading images/data over the web), the abstract windowing toolkit (AWT), and Swing.

Java Language, Utilities and Networking

Abstract Window Toolkit (AWT)

Java Swing

To import all of the classes within a package into a Java program, simply append ".*" to the package name. For example, the applet classes can be imported with the statement:

    import java.applet.*;

If you don't want to import all of the classes within a package, then simply name the classes you want in the import statement. For example, the statement:

    import java.net.URL;

imports a set of classes (contained within java.net) that can represent a uniform resource locator (URL).

Question 11 : What are the Java Foundation Classes (JFC)?

Answer : The production version of the Java Development Kit 1.2 (also
         called Java 2) was released in December 1998. The JDK 1.2
         contains a sophisticated set of graphics and user interface
         application interfaces called the Java Foundation Classes (JFCs).

Question 12 : What is the relationship between AWT, Swing and the JFCs?

Answer : The Java Foundation Classes contain five technologies:

         Accessibility API  -- Assistive technologies provide disabled
         people with additional assistance in using the user interface.

         Examples of assistive technologies include: speech recognition
         systems and screen magnifiers.

         Abstract Windowing Toolkit and Swing  -- The Abstract
         Windowing Toolkit (AWT) was launched with Java 1.0 and remains
         a key part of the JFC.

         When you write a user interface using Swing components, you still
         need to use the layout managers and event models supported by AWT.

         Java 2D Graphics API  -- The 2D Graphics API supports advanced
         2D Graphics and imaging.

         Drag and Drop  -- On native platforms supporting drag-and-drop
         (e.g., Windows 98), this technology provides drag-and-drop services
         between Java programs and native applications.

         Two of the key features of Swing are:

         Lightweight Components  -- Starting with the JDK 1.1, the AWT
         supports lightweight classes, meaning that the AWT classes do not depend
         on the classes of the underlying native system. Indeed, in Swing most
         of components have their own view supported by the Java look-and-feel
         classes.
 
         Pluggable Look-and-Feel  -- This feature enables a user to switch
         the look-and-feel of Swing components without restarting the application.

        For more information, see Pantham (1999).

Question 13 : Why should I upgrade my Java graphics from AWT to Swing?

Answer : The biggest difference between the AWT components and the Swing
         components is that the later are implemented with absolutely no
         native code. As a result, the Swing components are not restricted
         to the least common denominator (i.e., features common to every
         platform on which Java runs), and they can have more functionality
         than the AWT components.

         Examples of expanded functionality for the Swing components are
         as follows:

         1. New components for tables, trees, sliders, progress bars,
            internal frames and text components.

         2. Swing buttons and labels can display images instead of or in
            addition to text.

         3. Swing components don't have to be rectangular (e.g., Buttons
            can be round).

         4. You can easily add or change the borders drawn around most
            Swing components.

         5. The behavior or appearance of a Swing component can be easily
            changed by invoking methods on it or creating a subclass of it.

            For example, Swing components can have tooltips placed over
            them (a tooltip is a textual popup that momentarily appears
            when the mouse cursor rests inside the component's painting
            region).

         For more information on this topic, see Walrath (1999).

Question 14 : Are the AWT and Swing components designed to work together?

Answer : No.

Question 15 : What is the model-view-controller (MVC) architecture?

Answer : The swing components are based on the model-view-controller (MVC)
         design. Components of the MVC models are as follows:

         Model  -- The model encompasses the state data for each
         component.

         View  -- The view refers to how each component will appear
         on the screen.

         Controller  -- The controller is the portion of the user
         interface that dictates how the components interact with events
         (e.g., keyboard events, mouse clicks). The controller in each 
         component knows what events require an action and which events
         can be ignored.

         Each element in the MVC model requires information from the other
         elements to function properly. For details, see the adjacent
         figure.

Question 16 : How does the MVC architecture work in Swing?

Answer : The Swing components actually make use of a simplified variant
         of the MVC model called model-delegate. This design combines
         the view and controller objects into a single element that 
         draws the component to the screen and handles GUI events know
         as the user interface (UI) delegate.

         Bundling of the graphics capabilities and event handling in
         Swing components makes sense in Java because most of the event
         handling is taken care of by the AWT.

         A second purpose of the UI delegate is to react to various events
         that propagate through the component.

Question 17 : What is a JAR file and how do I use them?

Answer : A Java archive (JAR) file is a ZIP file that contains Java class
         files, auxiliary resource files required by those classes, and
         optional meta-information (e.g., a list of files contained within
         the JAR file).

         JAR files are created with jar, the Java archive tool.

Question 18 : What is a JavaBean?

Answer : The JavaBeans API provides a framework for defining reusable, embeddable,
         modular software components that can be manipulated visually in a 
         builder tool. Beans are characterized by the properties, events and
         methods they export.

         The most common use of beans is for graphical user interface components,
         such as those in the AWT and Swing packages. There are, however, no 
         limitations on bean complexity -- for example, embeddable spreadsheet
         applicaion programs have also been implemented as JavaBeans.

         For more information, see Flanagan (1999).

Question 19 : How can I run an applet?

Answer : The simplest way of running an applet is with the appletviewer.

         An appletviewer reads or downloads the one or more HTML documents
         specified by the filename or URL on the command line. Next, it
         downloads any applets specified in any of those files and runs
         each applet in a separate window. If the specified document or
         documents does not contain an applet, the appletviewer does nothing.

         In Java 1.1, the appletviewer recognizes applets specified with
         the <APPLET> tag. A simple implementation might look like:

            <html>
            <body>

            <applet code = "SimpleExample.class"
                    width = 200 height = 200
            </applet>

            </body>
            </html>

         Suppose that these markup tags are contained within a file
         called simple.html. To run the appletviwer, simply type:

         appletviewer simple.html

         This example assumes that SimpleExample.class file is located on
         the same machine as the appletviewer. The applet is displayed in
         a window having dimensions 200 by 200 pixels. More complicated
         implementations download the class file over the net and initialize
         the Java applet with parameter values...

         In Java 1.2 and 1.3, the appletviewer also recognizes applets specified
         with the <OBJECT> and <EMBED> tags. The java code page
         for this class contains numerous examples of these tags.

1. Campione M., Walrath K. and Humi A., The Java Tutorial, Third Edition , A Short Course on the Basics, Addison-Wesley, 2001.
2. Flanagan D., Java in a Nutshell 3rd Edition, O'Reilly, 1999.
3. Gutz S., Up to Speed with Swing , Second Edition, Manning, Grenwich, 2000.
4. Pantham S., Pure JFC Swing , SAMS Publishing, 1999.
5. Walrath K. and Campione M., The JFC Swing Tutorial : A Guide to Constructing GUIs, Addison-Wesley, 1999.

Developed in January 2004 by Mark Austin
Last modified: August 2008.
Copyright © 2004-2008, Department of Civil and Environmental Engineering, University of Maryland