EE2E1. JAVA Programming Introduction Dr. Mike Spann [email protected].

EE2E1. JAVA Programming

Introduction

Dr. Mike SpannDr. Mike Spann

[email protected]@bham.ac.uk

Contents

Java is just another programming language Java is just another programming language (eg. C & C++). So why bother to learn (eg. C & C++). So why bother to learn Java?Java?

Java is ……

PortablePortable Object orientedObject oriented RobustRobust Multi-threadedMulti-threaded GraphicalGraphical ConnectedConnected ExtensiveExtensive

Java applications and applets

ApplicationsApplications – standalone Java programs – standalone Java programs

Applets Applets – Java programs that run inside – Java programs that run inside web browsersweb browsers

‘Hello world’ application

/** * The HelloWorldApp class implements /** * The HelloWorldApp class implements an application that simply displays "Hello an application that simply displays "Hello World!" to the standard output. */ World!" to the standard output. */

public public class HelloWorldApp class HelloWorldApp { { public static void main(String[] args) public static void main(String[] args) { { System.out.println("Hello World!");System.out.println("Hello World!"); } } }}

‘Hello world’ appletclass HelloWorldPanel extends JPanel{ public void paintComponent(Graphics g) { super.paintComponent(g); Font f=new Font(“SansSerif”,Font.BOLD,36); g.setFont(f); g.drawString("Hello World!", 50, 120); }}public class HelloWorldApplet extends JApplet{ public void init() { Container contentPane = getContentPane(); contentPane.add(new HelloWorldPanel()); }}

‘Hello World’ html file

<APPLET CODE = “HelloWorldApplet.class" WIDTH = 300 HEIGHT = 300 >

</APPLET>

Run the ‘Hello World’ applet

http://www.eee.bham.ac.uk/spannm/Java%20Stuff/HelloWorldApplet/HelloWorldApplet.html

Portable Java

Java is ‘program once – run anywhere’Java is ‘program once – run anywhere’ A Java program is compiled to A Java program is compiled to bytecodesbytecodes Bytecodes interpreted by the Bytecodes interpreted by the Java Virtual Java Virtual

MachineMachine

Object Oriented Java

Object oriented programming is concerned Object oriented programming is concerned

with objects and their :with objects and their :

StateState BehaviorBehavior

ExampleExample A bank accountA bank account

transfer()

withdraw()

balance

account numberState

Behaviour

class BankAccount{

public void transfer(int amount);

public void withdraw(int amount);

private:int balance;int accountNumber;

}

Robust Java

Java is easier than C or C++!Java is easier than C or C++! Java has better memory management Java has better memory management

than C or C++than C or C++ You don’t need pointers for accessing You don’t need pointers for accessing

arrays or strings in Javaarrays or strings in Java No chance of dangling pointers or No chance of dangling pointers or

memory leaks in Javamemory leaks in Java

Multi-threaded Java

A A threadthread is a sequence of executing is a sequence of executing statements in a programstatements in a program

A multi-threaded program comprises a A multi-threaded program comprises a number of threads which run in parallel number of threads which run in parallel (but only one thread is being executed at (but only one thread is being executed at one time)one time)

Java supports multi-threading as an Java supports multi-threading as an intrinsic part of the language – multi-intrinsic part of the language – multi-threading is easy in Java!threading is easy in Java!

A single-threaded program

A multi-threaded program

Example – A sort demo

Multi-threaded Sorting Applet

Graphical Java

Abstract widget toolkit (AWT) + User Abstract widget toolkit (AWT) + User interface library interface library SwingSwing

Swing is a collection of user interface Swing is a collection of user interface components (buttons, menus, dialogue components (buttons, menus, dialogue boxes etc)boxes etc)

AWT does the event handlingAWT does the event handling

Example 1. A tic-tac-toe applet

http://www.eee.bham.ac.uk/spannm/Java%20Stuff/TicTacToeApplet/example1.html

Example 2. Full swing set demo

http://www.eee.bham.ac.uk/spannm/Java%20Stuff/SwingSetApplet/SwingSetApplet.html

Connected Java

Networking is easy in Java!Networking is easy in Java! Java has classes and methods for network Java has classes and methods for network

programming.programming. A Java program can easily access a web-A Java program can easily access a web-

site through a URL connectionsite through a URL connection Java programs can be be written which Java programs can be be written which

implement both client and server side implement both client and server side processingprocessing

Example – simple web browser

http://www.eee.bham.ac.uk/spannm/Java%20Stuff/BookMarkApplet/BookMark.html

So what is Java?

Java consists of 2 things :Java consists of 2 things :

The The Java Virtual MachineJava Virtual Machine (Java VM) (Java VM)

The The Java Application Programming Java Application Programming InterfaceInterface (Java API) (Java API)

Java VM runs the Java bytecode on the Java VM runs the Java bytecode on the different hardware platformsdifferent hardware platforms

Java API Java API is a large collection of ready-is a large collection of ready-made software componentsmade software components You can add additional API’s to this You can add additional API’s to this

layerlayer Graphics, numerical, image processing Graphics, numerical, image processing

etcetc The Java API is grouped into libraries of The Java API is grouped into libraries of

related classes and interfaces; these related classes and interfaces; these libraries are known as libraries are known as packagespackages. .

My Java program

Java API

Java VM

Hardware

Other API’s

Java APIjava

lang awt io

Math

String

Thread

Graphics

MathButton

Color

File

InputStream

OutputStream

sqrt()

exp()

Java API documentation can be found online at :

http://docs.oracle.com/javase/7/docs/api/

Extensive Java – Java technology

Java has additional API’s covering a wide Java has additional API’s covering a wide range of software technologiesrange of software technologies Java2D – 2D graphicsJava2D – 2D graphics Java3D – 3D graphicsJava3D – 3D graphics Java Advanced Imaging (JAI) – image Java Advanced Imaging (JAI) – image

processing processing

Java Speech API – speech processingJava Speech API – speech processing Java Media Framework API – multi-Java Media Framework API – multi-

media applicationmedia application JavaBeans – re-useable user interface JavaBeans – re-useable user interface

componentscomponents Java Servlets – extending web server Java Servlets – extending web server

functionalityfunctionality Java Message Service (JMS) – allowing Java Message Service (JMS) – allowing

programs to exchange messagesprograms to exchange messages Java Telephony API – computer telephonyJava Telephony API – computer telephony

Java TV API – interactive digital TVJava TV API – interactive digital TV

JavaMail API – email applicationsJavaMail API – email applications

JDBC – Java database APIJDBC – Java database API

Examples

Java2D APIJava2D API http://www.cs.kent.ac.uk/people/staff/pgk/www.cs.kent.ac.uk/people/staff/pgk/

teaching/java/lab-guides/getting-started/teaching/java/lab-guides/getting-started/demo/jfc/Java2D/Java2D.html demo/jfc/Java2D/Java2D.html

Java 3D APIJava 3D API http://www.mol3d.com/ http://www.mol3d.com/

Java resources Sun’s Java home pageSun’s Java home page

http://java.sun.com/http://java.sun.com/ Java online tutorialJava online tutorial

http://java.sun.com/docs/books/tutorial/http://java.sun.com/docs/books/tutorial/ Comparing C++and JavaComparing C++and Java

http://www.compapp.dcu.ie/~renaat/projects/cvjava.htmlhttp://www.compapp.dcu.ie/~renaat/projects/cvjava.html TextbookTextbook

Core Java 2. Volume 1-FundamentalsCore Java 2. Volume 1-Fundamentals C.S.Horstmann, G. CornellC.S.Horstmann, G. Cornell

Amazon LinkAmazon Link My web pageMy web page

http://www.eee.bham.ac.uhttp://www.eee.bham.ac.uk/spannm/Courses/ee2e.htmk/spannm/Courses/ee2e.htm

OK, so why should I learn Java?

Main reason, Java is Main reason, Java is object orientedobject oriented What is OOP good for?

Modelling asynchronously interacting objects• GUIs• Event simulation• Ray tracing visualisation• CAD simulation• Real-time control/embedded systems• Robotics• Image/Video processing• Client/Server systems• etc

OK, so why should I learn Java?

Java is free to download and is easy to learnJava is free to download and is easy to learn Java has powerful (and free!) development tools e.g. Eclipse , Java has powerful (and free!) development tools e.g. Eclipse ,

NetbeansNetbeans Excellent documentation support – JavadocsExcellent documentation support – Javadocs Great community supportGreat community support Rich collection of open source librariesRich collection of open source libraries Can develop Android apps in Java – supported by Eclipse and Can develop Android apps in Java – supported by Eclipse and

NetbeansNetbeans Android is a good platform for mobile apps because of Android is a good platform for mobile apps because of ease of

release, wide range of devices and its an open platform

So what about this course? EE2E1 (MS)EE2E1 (MS)

Introduction to Java programmingIntroduction to Java programmingBasic ideas about objects and classesBasic ideas about objects and classesWe will also look at more advanced features of JavaWe will also look at more advanced features of Java

• GraphicsGraphics• Files and streamsFiles and streams• Multi-threadingMulti-threading• NetworksNetworks

EE2E2 (DP)EE2E2 (DP) Object Oriented Software DesignObject Oriented Software Design

Assessment

EE2E1 and EE2E2 are assessed jointly (making up EE2E1 and EE2E2 are assessed jointly (making up the EE2E module)the EE2E module)

EE2E1 is assessed through a classtest and EE2E1 is assessed through a classtest and programming exercises and a major programming programming exercises and a major programming assignmentassignment 15% through a 1 hour class test15% through a 1 hour class test 2 x 22.5% through 2 programming exercises2 x 22.5% through 2 programming exercises 40% through a major programming assignment 40% through a major programming assignment

carried out in semester 2carried out in semester 2