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" |
New on the Java Boutique:
New Review:
Time Management Made Easy with the Quartz Enterprise Job Scheduler
Why not just use the Java timer API? This open source scheduling
API boasts simplicity, ease-of-integration, a well-rounded feature
set, and it's free!
New Applet:
Reverse Complement
Reverse Complement is a simple applet that converts DNA or RNA
sequences into three useful formats.
Elsewhere on internet.com:
WebDeveloper Java
Lots of Java information on webdeveloper.com
WDVL Java
Thorough Java resource at the Web Developer's Virtual Library.
ScriptSearch Java
Hundreds of free Java code files to download.
jGuru: Your View of the Java Universe
Customizable portal with online training, FAQs, regular news updates, and tutorials.
|