Showing posts with label java programming. Show all posts
Showing posts with label java programming. Show all posts

Friday, December 31, 2010

Getting Started

Alright, I've got the blog and the goal of teaching myself Java programming. What's next?

The first thing I did was found the Java download page:
http://www.oracle.com/technetwork/java/javase/downloads/index.html

I downloaded and installed the JDK (Java development kit) + NetBeans bundle. It took forever to download and install and even longer to load NetBeans once it was installed. So I uninstalled NetBeans and Java and went back and downloaded the JDK by itself. That's all you really need to get started. Well that and a text editor, but there are more text editors than I care to list.

So, I'm now armed with a new programming language, but I don't know how to use it. I need some help. I searched and found the Java documentation at:
http://www.oracle.com/technetwork/java/javase/downloads/index.html#docs

I downloaded and unzipped the files to my Java install folder. I clicked the index file and my web browser opened and a couple clicks later I was starting the "Hello World" tutorial: http://download.oracle.com/javase/tutorial/getStarted/cupojava/win32.html

So here's the tutorial.

Open Windows Notepad (Programs > Accessories > Notepad). Type the following text:
/**
 * The HelloWorldApp class implements an application that
 * simply prints "Hello World!" to standard output.
 */
class HelloWorldApp {
    public static void main(String[] args) {
        System.out.println("Hello World!"); // Display the string.
    }
}


Save this file as "HelloWorldApp.java". Make sure you type correctly. Java is case sensitive. That means "HelloWorldApp.java" is not the same as "helloWorldApp.java".


Open a command prompt (Programs > Accessories > Command Prompt) and navigate to where you saved "HelloWorldApp.java". To do this, type CD followed by the directory path. Here's a picture to show what I mean:

You should see your command prompt change

Type the following command and press Enter:
javac HelloWorldApp.java
This gives us a new class file
We run our new class file with the following command:
java HelloWorldApp
That's our first Java application!