CS 4773 Object Oriented Systems
About the course

Syallabus

First Assignment

What the course is not.

What the course is.

What is Java?

• simple
• object-oriented
• distributed
• interpreted
• robust
• secure
• architecture-neutral
• portable
• high-performance
• multithreaded
• dynamic
• general-purpose

• buzzword-compliant

Most notable is what it does not contain:

• global variables outside the class hierarchy
• goto
• pointer arithmetic
• malloc and free
• system dependent data types
• varargs
• separate header files
• preprocessor
• structures
• simple types passed by reference
• multiple inheritance
• operator overloading

Setting up your account

Compile with
javac programname.java

Run applications with
java programname

Run applets with
appletviewer programname.java

This assumes that your java source has an HTML heading as a comment.

Test to see that your path is set correctly by executing:
which javac

Ther result should be:
/usr/local/java/jdk1.1.5/bin/javac

First Assignment Example

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;

public class ShowD extends Applet implements ActionListener {
   Label prompt;
   TextField input;
   double val;

   public void init() {
      prompt = new Label("Enter a number");
      add(prompt);
      input = new TextField(20);
      input.addActionListener(this);
      add(input);
      setBackground(Color.cyan);
   }

   public void paint(Graphics g) {
      g.drawString("The number is: "+val,50,80);
      g.drawString("One hundred times the value is: "+100*val,50,110);
      g.drawString("This program was modified by Steven Robbins",50,150);
   }

   public void actionPerformed(ActionEvent e) {
      if (e.getSource() == input) {
         val = Double.valueOf(input.getText()).doubleValue();
         repaint();
      }
   }

}

This creates a file called ShowD.class

Run this using:
appletviewer ShowD.java

Put it on the web!

Next topic: The Java Language