Problem Solvingwith OOPand Java

Problem Solving

with OOP

Welcome To

and Java

Who Should Learn Java?

Have you done some programming?

Do you want to learn Java?

Do you prefer stimulating dinner conversations over coffee to dry, dull, technical lectures?

Do you need this course to graduate?

Java?

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Java?

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What Is A Computer?

A computer is something that takes in information (input), processes it according to a set of instructions (program), and produces a result (output).

Computers communicate through a binary alphabet. The letters in this alphabet are ‘0’ and ‘1’. Everything else is made out of these ‘letters’ which are called bits.

Bits are represented in a computer by electrical signals: low voltage would mean a ‘0’ and higher voltage a ‘1’. Eight bits gathered together form one byte.

What Is JAVA?Java is a free, open-source, Object Oriented Programming (OOP) language – everything is contained inside classes and objects.

Java is portable – it can run on any machine with a Java Virtual Machine (JVM) installed.

No matter what computer you have, you can write the same Java programs.

How WE use Java

Source Code

Compiler

Java byteco

de

Virtual

Machines

Source Code

Compiler

Java bytecode

Virtual Machines

How WE use Java

source code

class file

Code Structure in Java

method 1statement

method 2statementstatement

Collection of Java files

contains many classes

A classaclass.java

contains many methods and variables

public class aclass{public void

method() {

}

}

What goes in the source file?

A source file (with the .java extension) holds one class definition. The class represents a piece of your program, although a very tiny application might need just a single class. The class must go within a pair of

curly braces

public class Bicycle {

}

class

The source file MUST have the same name as the class. For example, the Bicycle class must be stored in the Bicycle.java file.

A class is the blueprint from which individual objects are created.

What goes in a class?A class has one or more methods. In the Bicycle class, the pedal method will hold instructions for how the Bicycle should pedal. Your methods must be declared inside a class (in other words, within the

curly braces

public class Bicycle{

void pedal( ) {

}}

method

of the class).

A bicycle might have some methods such as: speedup(), break(), gear(), direction()…

What goes in a

method?Within the

curly braces public class Dog {void bark ( )

{

statement1;

statement2;

statement3;

}}statements

of a method, write your instructions for how that method should be performed. Method code is basically a set of statements, and for now you can think of a function or procedure.

public class Bicycle{

void pedal( ) {

}}

statement1;statement2;statement3;

One Blueprint Can Be Used To Help Build Different

Objects

Shape

rotate ( )playSound ( )

Square Triang

le

Circle Amoeba

This is called inheritance

EVERYTHINGis made from OBJECTS

Shape

rotate()playSound()

Object

equals()getClass()hashCode()toString()

Circle

doSomething()

This is the Object class from which ALL other objects are created.

What You Will Get Out Of Learning and Using

Java!Build your programming skills and confidence.

A thorough understanding of Object Oriented Programming.

Learn a language that can be run on any platform.

Learn how to work and program in groups.

Develop Graphical User Interfaces.

Where To Start

Setup Eclipse Classic

Write your first Java program

If you can, bring your laptops to class every lecture!