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 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 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 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 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 Last year s best version Java 1 4 The latest and best version 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 Integrated Development Environment A tool that makes it easier to write programs 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 BlueJ BlueJ is an IDE Integrated 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 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 What You Need 48 MB of RAM 64 MB recommended 166 MHz Pentium or better Macintosh must run Mac OS X SDK 1 4 includes JRE BlueJ 1 2 Earlier versions do not fully support Java 1 4 By the way the SDK and BlueJ are free Getting Ready If you plan to use your own computer Download and install Java SDK 1 4 http java sun com j2se 1 4 download html Download J2SETM v 1 4 0 02 Windows all languages including English SDK Download and install BlueJ 1 2 http www bluej org Optional Download the Java documentation http java sun com j2se 1 4 download html J2SE 1 4 Documentation The End
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