1. 1 Java Java E-Commerce Prof. Sheizaf Rafaeli

2. 2 E-Business : Java intro: Prof. Rafaeli What is Java? n n A fundamentally new way of computing, n n Based on the power of networks n Write once -- run anywhere –450 million vs. 120 million? n n With Java technology, you can use the same application on any kind of machine -- a PC, a Macintosh computer, a network computer, a Ford car or a Krups coffee pot, or even new technologies like Internet screen phones.

3. 3 E-Business : Java intro: Prof. Rafaeli Java Hype n n Java could surpass Windows as the software platform with the world's largest base by the turn of the century. (which century?) n n "All of you who have anything to do with software development ignore JAVA at your own peril" " JAVA - TODAY THE WEB, TOMMOROW THE WORLD!!"

4. 4 E-Business : Java intro: Prof. Rafaeli “Thin clients” n n Computers designed to be centrally-managed n n Configured with only essential equipment n n No CD-ROM, disk drives or expansion slots n n Therefore lower in cost, esp. Cost-Of-Ownership. Net PC (Intel and Windows) NC (Oracle and Sun) Web TV

5. 5 E-Business : Java intro: Prof. Rafaeli Client systems range from dumb terminals to mostly autonomous PCs. Thin clients fall in between. ( Source: Byte Magazine)

6. 6 E-Business : Java intro: Prof. Rafaeli Why is Java important? n n With Java technology, the Internet and private networks become your computing environment. n Remote computing, thin clients, distributed control and access n Java animates the Web, makes it interactive, distributes content and power, and transforms the internet and information systems.

7. 7 E-Business : Java intro: Prof. Rafaeli How it works (in a web browser) References to java software (applets) are embedded in HTML The Java virtual machine first does stringent security checks, and then runs the applet, which appears and interoperates inside the browser.

8. 8 E-Business : Java intro: Prof. Rafaeli Java’s Secret: the Virtual Machine (VM) Virtual Machine: a layer of software just above the CPU that emulates a theoretical ("virtual") chip's behavior. It hides--or Abstracts--the machine-level stuff into a single layer of software. The Java Virtual Machine, when properly implemented, allows a Java application to run on the CPU for which the VM is written, regardless of the type of system on which the Java programmers worked.

9. 9 E-Business : Java intro: Prof. Rafaeli How it works (2) (in a web browser) The computer's operating system provides machine-specific support for many of the actual operations and interactions. Result: The user gets an interactive Java applet running in a browser. The Java virtual machine serves as consistent platform on different kinds of computers and operating systems, so that the same Java applet runs in browsers on PCs, Macs, UNIX, PDAs, workstations, Network Computers, and elsewhere.

10. 10 E-Business : Java intro: Prof. Rafaeli How it works (3)

11. 11 E-Business : Java intro: Prof. Rafaeli Java’s Promises n Simple –like and unlike C, C++ n Object Oriented n Distributed n Robust –careful at handling data types –no pointers n Dynamic – –adaptable n Secure n Portable, small –no implementation- dependent aspects n High Performance –could be better –still hybrid compile/interpret n Multithreaded

12. 12 E-Business : Java intro: Prof. Rafaeli Java’s Perils   A native OS might offer features that Java can't use without sacrificing cross-platform compatibility.   Interpreted Java byte-code doesn't run as fast as complied native code.   If a program must interact with legacy code or data, a more established tool or language might work better.   A developer may have superior tools for another language or may be more productive using a familiar tool or language.   A developer may not want to change, even if it costs money and customers.

13. 13 E-Business : Java intro: Prof. Rafaeli Java is not JavaScript n Java is n Java is a full-fledged object- oriented programming language. Hybrid JIT compilation to byte code. n n can be used to create standalone applications n n Both client and server side, and used much in stand-alone embedded environments. n n Owned by Sun n Interpreted, does not create applets or standalone applications n Mostly client side, but some server software, (Netscape's SuiteSpot), lets developers write CGI programs in a server- side version of JavaScript. n Owned by Netscape A Java-enabled browser is not automatically a JavaScript-enabled browser: they require entirely separate interpreters (licensed from separate companies) Rather than competing with each other, Java and JavaScript are a powerful combination.

14. 14 E-Business : Java intro: Prof. Rafaeli Applets Applets vs. applications

15. 15 E-Business : Java intro: Prof. Rafaeli Anatomy of an Applet Reference code heightwidth codebase alignhspacevspace name Imagine an impressive Java applet here

16. 16 E-Business : Java intro: Prof. Rafaeli Example <param name=MessageText value="Bookmark this page!"> Bookmark This Page!

17. 17 E-Business : Java intro: Prof. Rafaeli Java applet restrictions n Not too fast! n Byte code, not compiled n No (or limited) access to files n Applets have no memory-- they are stateless (however secure servers allow bypass) n Limitations on number of sockets open (connections) n How much of a closely held property of and by Sun Microsystems?

18. 18 E-Business : Java intro: Prof. Rafaeli Microsoft vs. Sun? n Scott McNealy vs. Bill Gates? n Sun thinks (hopes?) that Java will be an alternative to Windows n Microsoft thinks otherwise… n Others now in the game Source: Fortune Magazine http://www.javasoft.com/lawsuit/index.html

19. 19 E-Business : Java intro: Prof. Rafaeli Microsoft vs. Sun (2)

20. 20 E-Business : Java intro: Prof. Rafaeli C sharp (C#) n n After settling its Java lawsuit with Sun Microsystems, Microsoft announced a new set of software development tools and services that will allow Java programmers to support Microsoft's new software strategy. n n Called Java User Migration Path to Microsoft.Net, or JUMP to.Net n n Microsoft will also ship a tool that converts Java software code to C# code. C# (pronounced "C-sharp") is a Java-like language that Microsoft has created to compete against Java. C# is an object-oriented programming language. It aims to combine the computing power of C++ with the programming ease of Visual Basic. C# is based on C++ and contains features similar to those of Java.object-oriented programmingC++ Visual BasicJava

21. 21 E-Business : Java intro: Prof. Rafaeli How, where, by whom is Java used?  Check out Sun’s report, at  http://www.javasoft.com/nav/used/  http://industry.java.sun.com/javanews/more/success/  See JARS and GAMELAN  C & L experiment with office  Wordperfect office suite?  Net-It

22. 22 E-Business : Java intro: Prof. Rafaeli How, where, by whom is Java used? (2) n

23. 23 E-Business : Java intro: Prof. Rafaeli Embedding an applet on your page n n You can find the applet.class files in your browser's on-disk cache and copy them n n To be used locally n n Or on your own server

24. 24 E-Business : Java intro: Prof. Rafaeli Embedding a remote applet on your page n n n Try the applet on –http://mis.huji.ac.il/ttt/java.lecture.html –and on http://www- personal.umich.edu/~sheizaf/tryjava.html

25. 25 E-Business : Java intro: Prof. Rafaeli How to enable/disable Java Netscape 3.0 n n Go to "Options | Network Preferences..." from the main menu n n Change to the "Languages" tab To enable: make sure "Enable Java" check box is checked n n To disable: make sure "Enable Java" check box is unchecked n n Restart the browser

26. 26 E-Business : Java intro: Prof. Rafaeli How to enable/disable Java Netscape 4.x (Communicator) n n Go to "Edit | Preferences..." from the main menu n n Select "Advanced" panel To enable: make sure "Enable Java" check box is checked. n n To disable: make sure "Enable Java" check box is unchecked. Restart the browser

27. 27 E-Business : Java intro: Prof. Rafaeli How to enable/disable Java Explorer   Go to "View | Options..." from the main menu   Change to the " Security " tab   To enable: make sure " Enable Java programs " check box is checked   To disable: make sure " Enable Java programs " check box is unchecked   Restart the browser

28. 28 E-Business : Java intro: Prof. Rafaeli How to enable/disable Java Explorer 4.x and 5.x   Go to "View (or Tools) | Internet Options..." Change to the " Security " tab   Select "Custom" and click on the " Settings..." button   To enable: make sure " Disable Java " is selected under " Java." To disable: make sure a setting other than "Disable Java" is selected under " Java." If you're not sure which setting to choose, select " High safety "   Restart the browser

29. 29 E-Business : Java intro: Prof. Rafaeli Sample IDE for Java online * Try the online Java Web IDE at: *http://www.chami.com/webide/ * Try JXXX Online Java compiler: http://www.cybermeister.net/java/stepone.html * Check out Symantec’s “Café”, Visual Café Pro, IBM’s “Visual Age for java”. * Borland, Microsoft’s Visual J, Lotus   Sybase PowerJ Metrowerks CodeWarrior Inprise Jbuilder Supercede for Java Sybase PowerJMetrowerks CodeWarriorInprise Jbuilder Supercede for Java

30. 30 E-Business : Java intro: Prof. Rafaeli Java & Security? H Java’s “sandbox” security model H Active-X “trust” model H In any case, H In any case, safe network computing is an oxymoron H H Orange Juice works better

31. 31 E-Business : Java intro: Prof. Rafaeli The 10 Java Buzzwords 3 Java Virtual Machine 3 HotJava, Appletviewer, javac,. “Servlets” 3 JDK, Java Development kit 3 JAR, zip, & Java Beans 3 “Sandbox” vs. “Trust” security models 4 AWT, Abstract Window Toolkit 4 ByteCode 4 JIT Compiling 4.class,.java (source and bytecode) 4 JDBC, Java Database Connectivity ODBC in Java

32. 32 E-Business : Java intro: Prof. Rafaeli Java Glossary and cheatsheets n Try StepOne: http://www.cybermeister.net/java/stepone.html n http://www.mindprod.com/gloss.html n http://www.freewarejava.com/ n http://metalab.unc.edu/javafaq/javatutorial.h tml n http://www.javacoffeebreak.com/ n http://java.sun.com/docs/books/tutorial/ n http://www.mercury.com/java- tutor/session01/session01.html

33. 33 E-Business : Java intro: Prof. Rafaeli The “Java backlash”  “It still does nothing” (?)  Does the world really need programmable toasters?  How long does it take to develop, load, run?  Will Microsoft succeed in busting the “platform agnostic” monopoly buster?  Animation, interaction and dynamic content easier to achieve with DHTML  Is it truly slow, secure, portable?

34. 34 E-Business : Java intro: Prof. Rafaeli Is Java taking root?  In the browser  On the server (servlets)  As commercial applications  In the arena of enterprise applications  In teaching institutions  For some bubble bursting and iconoclasm, see:  http://www.disordered.org

35. 35 E-Business : Java intro: Prof. Rafaeli A few more, and URLs  Gamelan, JARS, Developer  http://java.sun.com http://www.javaworld.com  http://www.phrantic.com/scoop/onjava.html  Best Java tutorial at: http://www.phrantic.com/scoop/onjava.html   IBM’s introduction to java, at:  http://www.ibm.com/java/education/intro/courseoptions.htm/  http://www.zdnet.com/products/garage/java/applet/  “Java in five minutes” http://www.zdnet.com/products/garage/java/applet/  Java in the future:  Windows, or OS/2 and hypercard?