The Java Boutique: Java Tutorial: Java by Example: Java Basics

Tutorials : Java by Example : Section 1 :

Section One Contents

If, Else and Switch: Basic Control Structures

Java Basics

Simple Methods And Basic Data Types

Here you can see how to use a simple method with one parameter. The parameter is used to change the y-coodinate of the text output. Everything that is done more than once should be put into a method to make it re-usable.

//Sourcecode

import java.awt.*; import java.applet.*; //Introduces methods public class Project2 extends Applet { //We need a global graphics object if //we use functions which use graphics: public Graphics g; //This is our method. It's only parameter is //the y-coordinate of the text string. public void Hallo(int y) { g.setColor(Color.black); g.drawString("Hallo Java!",120,y); } public void paint (Graphics gr) { g=gr; //We call our method several times //with different parameters Hallo(50); Hallo(100); Hallo(150); Hallo(200); Hallo(250); } }

The most common basic variable types in Java are:

Name What is it Range Example

boolean logical true or false true

int 32 bit signed number -2³¹ .. +2³¹-1 123789

long 64 bit signed number -2⁶³ .. +2⁶³-1 123456789

float 32 bit floating point number ca. 7 places accuracy 3.14

double 64 bit floating point number ca. 15 places accuracy 0.00032424

String text - "This is a text"

Applet Index
(sorted alphabetically)
A B C D E F G H I J K
L M N O P Q R S T U
V W X Y Z #s

The Java Source
(applets w/source code)
A B C D E F G H I J K
L M N O P Q R S T U
V W X Y Z

How to Add Java Applets to Your Site

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