Java : Tutorial

I'm on the Java Trail. The trail is a way to learn Java. I'm not too positive about many online tutorials. Except the ones from Coronado of course, but this one is rather good. So spend some time on them. They're free, accessible and well maintained. Apart from the comment boxes below each trail section. These show how intelligent the audience is.

Here is the Java trail: http://java.sun.com/docs/books/tutorial/java/index.html .

Trail: Getting Started

How original. The first section of the trail is a kind of commercial for Java. In the second part, programming is introduced. We start with the obligatory 'Hello world' but I changed the text to something more of this time:

/**
 *  * 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("Hi there!"); // Display the string.
     }
}
   
You compile and run it with these commands:
jan@Beryllium:~$ cd develop/java/
jan@Beryllium:~/develop/java$ jed HelloWorldApp.java
jan@Beryllium:~/develop/java$ javac HelloWorldApp.java
jan@Beryllium:~/develop/java$ ls
HelloWorldApp.class  HelloWorldApp.java
jan@Beryllium:~/develop/java$ java HelloWorldApp
Hi there!
jan@Beryllium:~/develop/java$
   
Good enough for a first experiment I guess. The explanation in the Tutorial Trail is very good.

Trail: Learning the Java Language

In this section, the first two parts deal with objects and classes. In Europe (where I live) 'class' is a loaded word. It is always associated with communism and the philosophers Marx and Engels. 'Class' is something some people pretend to have. They show off their 'class'.
This special undertone for the word 'class' has always slowed me down. But in this tutorial, the writers have found the right pitch to brings objects, methods, class and the lot to life. 'Class' is described by means of a bicycle. And a dog is an object, which can be in the 'hungry' state.

Findings

Keep in mind that I am a (not so) seasoned Modula-2 programmer. What I miss in seasonedness, I make good with knowledge of the background of the language and compiler. Still, after reading through less than 20 webpages of Java Tutorial, I must confess that:

More to come.

All in all I must confess I matured a lot since my previous attempts with Java. Or Java matured that same amount. Or we both did. Anyway: Java looks rather impressive at the moment.

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