Java Tutorial

Wayne Summers
summers_wayne@ColumbusState.edu
New Mexico Highlands University
http://csc.ColumbusState.edu/summers/Notes/Java.htm

The Java Programming Language is a portable, interpreted, high-performance, simple, object-oriented programming language with a supporting run-time environment.

• Java History -
  • developed by Sun Microsystems in 1991 as part of the Green project and originally named Oak;
    first used in developing an interface for a PDA (Personal Data Assistant)
  • Used with the Web in 1994 (HotJava browser released)
  • Introduced by Sun at SunWorld, May 1995

• Java's Place in the Object-Oriented Continuum - based on C++ but for a multiplatformed environment

• Defining Java - multithreaded OOP with support for multimedia and animation
  • Java Applet Definition - form of Java programs designed to run on a Java-compliant web browser (Netscape 3.0+ and IE 3.0+)

• The Benefits of Java
  • Java is Object-Oriented
  • Java does not use visible pointers
  • Java is based on single inheritance
  • Java has automatic memory management and garbage collection
    • compaction - defragmenting memory
    • Marking and sweeping - marks objects in use and "sweeps" non-marked objects
  • Java supports overloaded functions, but not overloaded operators; no struct or union
  • Java does not support automatic coercion (type-casting)
  • Java has a native string object
  • Java is multithreaded
  • JAVA IS PLATFORM-INDEPENDENT (runs in a multiplatform environment)
    source computer's compiler translates source code into bytecodes which are interpreted on the client
  • Java is verified - bytecodes are checked for security violations

• The Negatives of Java
  • JAVA IS SLOW (applet must be downloaded, verified, and interpreted before it is run)
  • IDE still being developed (but better than when the book was written)
  • security limits access to files and interaction with other servers

• Java Development Environments
  • Java Developer's Kit(JDK)
    contains source code for classes and has several nice facilities but lacks a GUI front-end
    • javac.exe - compiler (compiles Java source code into bytecode file with .class extension)
    • java.exe - interpreter (interprets and runs bytecode file)
    • jdb.exe - debugger
    • javah.exe - generates C headers from Java-compiled classes
    • javap.exe - class disassembler (bytecodes to source code)
    • javadoc.exe - used to create HTML pages from the source code
    • appletviewer - looks for and utilizes APPLET tags in the HTML page
    • Detailed Instructions for Your First Program
  • Symantec Cafè - commercial product that contains GUI interface and other enhancements
  • Borland Internet Products - commercial product Latte (now called JBuilder) similar to C++Builder and Delphi [available in SCA205 lab]
  • Java Workshop - Sun's GUI environment used to create Java Applets and programs as well as HTML pages
  • Microsoft's Visual J++ [available in LH2 & SCA205 lab]
    • visual tool that uses standard GUI development techniques (resource builders, syntax-aware editors, graphical debuggers]
    • integrated with Visual C++ and Visual BASIC
    • enables the developer to extend the capabilities of the Java language

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  Java Programs
  
  

  Simple Java Programs Hello.java Temperatures.java DemoInput.java ComputePay.java (with errors) ComputePay.java (corrected) ClassRank.java BankBalance.java DemoDates.java

  Simple Java Applets Applet Syntax Simple Hello World Hello World with a Graphic Logo Animated Logo Windows Applet Fibonacci Applet

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  Advanced Java Applet Programming
  
  
  • Graphics
  • Multithreading
  • Multimedia: Images, Animation, and Audio
  • Network Programming
  • Data Structures

  • Examples of Java Programs

  • Links to Java Sites and Resources
  • Java API

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