Java Programming, 3eConcepts and Techniques

Chapter 2Creating a Java

Application and Applet

2Chapter 2: Creating a Java Application and Applet

Chapter Objectives

• Write a simple Java application

• Understand the different types and uses of comments

• Use proper naming conventions for classes and files

• Identify the parts of a class header and method header

3Chapter 2: Creating a Java Application and Applet

Introduction

• Users enter data and instructions into a computer and receive feedback from the computer through a user interface

• Programmers can create many types of user interfaces in Java

• We will create a program with two types of user interfaces– Console application

• Command line interface

– Applet• Graphical user interface displayed in a browser

4Chapter 2: Creating a Java Application and Applet

The Welcome to My Day Program

• This program will display a splash screen– A splash screen is a screen that is displayed

before the main program starts

• The screen will contain a welcome message, user’s name, and system date – The console application will display text only– The applet will contain text, color, and a

graphic

5Chapter 2: Creating a Java Application and Applet

6Chapter 2: Creating a Java Application and Applet

Program Development

7Chapter 2: Creating a Java Application and Applet

Analysis and Design

• Verify that the requirements are specific enough

• Design the user interface using a storyboard

• Design the program logic using a flowchart and event diagram

8Chapter 2: Creating a Java Application and Applet

9Chapter 2: Creating a Java Application and Applet

10Chapter 2: Creating a Java Application and Applet

11Chapter 2: Creating a Java Application and Applet

Coding the Program -Comments as Documentation • Purpose of comments

– Provides clear description when reviewing code– Helps programmer think clearly when coding

• Placement of comments– Use a comment header to identify a file and its

purpose– Place a comment at the beginning of code for each

event and method– Place comments near portions of code that need

clarification

12Chapter 2: Creating a Java Application and Applet

Coding the Program -Comments as Documentation

13Chapter 2: Creating a Java Application and Applet

Coding the Program - Define the Project • For this assignment create a new project called

“Welcome” with a class of “welcome.Welcome”

14Chapter 2: Creating a Java Application and Applet

Coding the Program - The Class Header • Identify how the code can be accessed with an

access modifier– public indicates that the code can be accessed by all

objects in the program and can be extended for a subclass

• Specify a unique name for the class– The class name at the beginning of the program must

match the file name exactly– Java is case-sensitive – By convention, uppercase letters are used for class

names and to distinguish words in class names

15Chapter 2: Creating a Java Application and Applet

Coding the Program - The Class Header

• Use braces { } after the class header to enclose the class body

16Chapter 2: Creating a Java Application and Applet

The Welcome Class/* * To change this template, choose Tools | Templates * and open the template in the editor. */

package welcome;

/** * * @author gjschmidt */public class Welcome {

}

17Chapter 2: Creating a Java Application and Applet

Rest of Today

• Make sure you create and save your Welcome project

• Review your grade. Progress report grades are due on Friday.

• Make sure your write-up for the Alice project has been turned in.