Introduction to Java & Installing the SDK and BlueJ

Announce

• Start Attendance Sheets

• First quiz Friday

– Over common html tags

– Covers up to “Decision Trees” page 22 of your text.

– The quiz will be the second part of the class. When you finish the quiz, you may hand it in, then leave

• You should be reading Chapter 2 of the text

Object Oriented Programming

• Everything is treated as an object

• An object has two parts

– The attributes of the object (the data)

– The manipulation of the attributes

• First, a template for objects is declared

– In Java the template is called a class

• Then different instances of the template are created

The Java environment

• A text editor is used to record the high level java program in ASCII code

• A java compiler translates it into bytecode (J-code)

• A bytecode interpreter translates it into the machine language for the specific machine it is running on

The Java Platform

• First, you create the source code with a text editor

– This file is saved with a .java extension

• Next the source code is compiled into bytecode.

– this file is saved with a .class extension

• On the local machine an interpreter reads the bytecode and translates it into machine language for that specific machine.

– It is easier to write an interpreter for the Java bytecodes than it is to write a compiler for the Java source code

• This interpreter is included in modern browsers so that they can interpret bytecodes (i.e. run an applet)

Two ways of using Java

• Applications and Applets

– Applets

• programs that can be embedded in HTML documents.

• HTML has tags specifically designed for Java applets

– Applications

• Traditional programs that can run stand-alone from the command line or a GUI

• In Java, a main method is included in a class to make it an application

Getting started with Java

• The Java compiler, called the Java Development Kit (JDK) is provided free from Sun, who developed Java

– Now called the SDK (Sun Development Kit)

• The user interface to the SDK is fairly primitive

• BlueJ is a system that uses the SDK; it provides a GUI, designed especially for education

• There is a BlueJ tutorial (31 pages) provided by the developers of BlueJ, available for download free

– It is in Adobe Acrobat format.

Installing the SDK

• First you must go to the Sun site and download the SDK.

– You want the Standard Edition J2SE 1.4.0

– It is 30 MB, so if you have a slow connection you may prefer to buy a disk with it on.

• AWC is selling these disks for $3.00

• The name of the file is
j2sdk1_4_0_01-windows-i586.exe

• Notice that the extension is .exe

– This mean it is executable. When you double click on it, it will unzip itself an then install itself

• You must notice the name of the directory where it installs itself The default is C:\j2sdk1.4.0_01

Installing BlueJ

• BlueJ( www.bluej.org ) was developed at a University specifically for the purpose of teaching object orientation with Java

• The file you need to install BlueJ is
bluejsetup-121.exe

• If you click on this file it will also install itself.

– It will ask you where the SDK is stored. Be sure it is correct

– Then it will ask you where you want BlueJ. Anywhere is fine as long as you know where it is.

Learning to use the SDK and BlueJ

• For your PreLab, you will need to work through the BlueJ tutorial.

• This means you must have a copy of it before lab Tuesday!

• You can either download it from here and print it yourself, or pay Card n Copy for a copy of it

• There is also a reference manual you can view and print if you wish

• If you get error messages installing BlueJ, you should try the FAQs or Tip of the Week Archive on the BlueJ site

The BlueJ tutorial & reference manual

• Both are in Adobe Acrobat format

– This is a common format that allows people distributing information to get it to you all ready to print or view

– In order to view it, you must download the Adobe acrobat reader. It is free from Adobe

• It is also on the disk from AWC