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Getting Ready for Java

Getting Ready for Java. What is Java?. Java is a programming language: a language that you can learn to write, and the computer can be made to understand Java is currently a very popular language Java is a large, powerful language but it is not simple! Compared to C++, Java is elegant.

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Getting Ready for Java

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  1. Getting Ready for Java

  2. What is Java? • Java is a programming language: a language that you can learn to write, and the computer can be made to understand • Java is currently a very popular language • Java is a large, powerful language • but it is not simple! • Compared to C++, Java is elegant

  3. Declarations, statements, and comments • A declaration gives some information to the computer • A statement tells the computer to do something • Statements should really be called “commands” • Comments are ignored by the computer--they are explanations of your program for human beings to read

  4. Syntax and semantics • Syntax is the “grammar” of the language • The syntax of Java is large, but finite • Syntax must be absolutely correct • The computer will point out every syntax error • Error messages may be helpful or misleading • Semantics is the “meaning” of your program • Semantic errors cause your answers to be wrong • You may or may not get error messages

  5. Two aspects of Java • Java has syntax and semantics • This is where you begin • It is possible to learn everything about Java’s syntax and semantics • We will cover most of Java’s syntax and semantics • Java also has “packages” • Packages are sort of like vocabulary bundles • To be good at Java, you need to learn many packages • There are more Java packages than you can ever learn

  6. Versions of Java • Java 1 • Java 1.0: Original, not very good version • Java 1.1: Greatly revised and improved • Java 2 • Java 1.2: Includes “Swing” • Java 1.3: Currently the best version • Java 1.4 beta: The next version, still very buggy

  7. Vocabulary I • JRE, Java Runtime Environment • The software that allows you to run Java programs on your computer • JDK, Java Development Kit; also • SDK, System Development Kit • The software that allows you to create and run Java programs on your computer • IDE, Interactive Development Environment • A tool that makes it easier to write programs

  8. Vocabulary II • Beta software • Software that is new, untested, often buggy • Interface • the place where things touch each other • the way that distinct things communicate • GUI, Graphical User Interface • A way for the computer and the user to communicate via graphics (pictures) on the screen

  9. BlueJ • BlueJ is an IDE (Interactive Development Environment). It includes • an editor, which you use to write your programs • a debugger, to help you find your mistakes • a viewer, to see the parts of your program • an easy way to run Java programs • an easy way to view documentation

  10. Elegance • Powerful software can do everything you want to do--for example, Microsoft Word • Complex software is hard to learn and hard to use--for example, Microsoft Word • More power usually means more complexity • Elegant software somehow manages to be both powerful and simple • BlueJ is elegant

  11. What You Need • 48 MB of RAM (64 MB recommended) • 166 MHz Pentium or better • Macintosh: must run Mac OS X • JDK 1.3, preferably 1.3.1 • BlueJ 1.1.4 • does not work well with JDK 1.4 beta • By the way: the JDK and BlueJ are free

  12. Getting Ready • If you plan to use your own computer: • Download and install JDK 1.3.1 • http://java.sun.com/j2se/1.3/ • Download and install BlueJ 1.1.4 • http://www.bluej.org/ • [Optional] Download the Java documentation • http://java.sun.com/j2se/1.3/docs.html

  13. The End

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