Lecture 1: Computers, Programming, Java and Linux

What You Will Learn Today

1. Understand the structure and purpose of the course.
2. Locate course-related resources for independent learning.
3. Review concepts related to the programming process.
4. Compare the features of Java and other programming languages.
5. Describe how to create, compile and run a simple Java program.
6. Compare the features of Linux and Windows operating systems (separate handout).

Course Overview

• Course prerequisites
  • An introductory first-year programming course in C++ or C. Object-oriented knowledge is not assumed.
• Coursework
  • 5 programming assignments, 2 programming projects, final exam
• Course schedule
  • See the calendar for course meeting dates and times. Note: no class next week.
• Lecturer
  • Mr. G. Vogl, 077-606404, gvogl@umu.ac.ug (Nkozi Wed.-Fri.), GregVogl@yahoo.com (Kampala Sat.-Tue.)

Course Goals

1. Design, code, compile, run, test, debug, modify, and document programs
2. Explain and use programming concepts, algorithms and processes
3. Be prepared for further study of the software development aspects of computer science

Course Content

1. Review basic C-like language features of Java including:
   applications, variables, types, operators, expressions, statements, comments, I/O, selection, repetition, functions, arrays, strings
2. Use object-oriented features of Java including classes, inheritance, interfaces and polymorphism
3. Use basic algorithms (recursion, searching and sorting) and data structures (stack, queue, list)
4. Use Java applets, GUI components (AWT and Swing), two-dimensional graphics, event and exception handling
5. Use database and networking features

Key Resources

• Primary library textbook
  • Big Java, Horstmann, Prentice Hall, 2002, 005.133 HOR
• Photocopies
  • QuickStudy Guides: Java, Unix, C++
• Major electronic resources
  • Java 2 Software Developers Kit, including API documentation, and Java Tutorial
• Primary Intranet resource
  • course web site: http://home.umu.ac.ug/java/

Computers, Hardware and Software (Revision)

• digital electronics and number systems
  • bits/bytes, kilo/mega/giga, binary/octal/decimal/hexadecimal conversion
• functions of a computer system
  • processing, input, output, memory, storage, communication
• hardware components of a computer system
  • CPU, input, output, RAM, ROM, secondary storage, communication
• software components of a computer system
  • application software, system software, operating systems
  • program vs. programming language

The Programming Process (Revision)

• programming activities
  • obtain specifications, design an algorithm, write code, compile, run, test, debug, revise, document
• software development activities
  • project planning, resource management, analysis, specification, design, coding, testing, debugging, installing, training, supporting, documenting
• work roles involved in software development
  • project managers, systems analysts, subject matter experts, programmers, technical writers, testers, and end users

Features of Programming Languages (Revision)

• low level language vs. high level language
• machine language vs. assembly language
• procedural language vs. object-oriented languages
• compiled language vs. interpreted language
• hardware dependent language vs. portable language

Java Overview

• Java is a relatively new, powerful, general purpose, object-oriented programming language.
• Java is quite similar to C++ and probably easier for learning the basics.
• Java has extensive libraries for creating graphics and GUIs, interacting with databases, and creating Internet applications.
• Java applets are applications that can run over the Internet in a web browser.
• Java source code is compiled to produce a type of object code called byte code.
• Byte code is interpreted (translated into machine language) when a program loads.
• Java supports multithreading, garbage collection and document generation and has many built-in safety features.
• See the comparison of programming languages for differences from other languages (JavaScript, C, C++ and Visual Basic).

A Simple Java Program

// This program prints two string literals.
public class Hello
{
   public static void main (String[] args)
   {
      System.out.println("Hello, world!");
      System.out.println("My name is your name.");
   }
}

Creating the Source Code

• Start a text editor such as kedit or kate (for beginners) or emacs or vim (for advanced users).
• Type in the above program, replacing your name with your first and last name.
• Save the file with filename Hello.java into your account or onto a floppy disk.

Compiling the Program

• Open a shell window such as Konsole.
• If necessary, change to the directory where the file is located, e.g. type cd /mnt/floppy
• Compile the file by typing javac Hello.java
• If the compiler reports any errors, fix them and compile again.
• If no error is reported, type ls -l to see that a file named Hello.class has been created which contains the compiled byte code.

Running the Program

• To run the program, type java Hello
• You should see the following output:

Hello, world!
My name is your name.

To Do After Class

• Fill in the student survey form and return it to the lecturer at the beginning of the lab.
• Locate Java books in the library and briefly compare their format and contents. Read the first chapter of one to get further introduced to the language.
• Circle any words in these notes that you do not understand, look them up in a book, and write down their definitions using your own words.
• Log in to a computer running Linux and explore its programs, files and features.
• Type the above Java program into a text editor, compile and run it. Make some changes, recompile and run again.
• Browse and become familiar with the course web site (available soon).