Well i have started studying Java according to the Sun SCJP exam certification, and have just finished studying about the language fundamentals, so will add to the blog what i have learnt in addition to what i have already written.

Bren

Basically a method in Java is a list of instructions that has to be carried out when that method is called. For example, you may want to calculate the interest rate on a given amount,  you could create a method then called WorkOutInterest. In this method you would then give the instructions on how to work out the interest rate for that given amount. To declare a method in Java you write it like this

void WorkOutInterest() {
…. //Code here to work out interest}

Now that we have our method on how to work out the interest rate of an amount we now have to be able to use this, this is done by calling the method, a method call. At the moment we are not going into too much detail about all of this but just taking a look at it. So our method call could look like this

WorkOutInterest(firstAmount);

So now we have our method declaration and our method call. The method declaration basically just tells the computer what to do when that method is called into action and the method call tells the computer to actually do the set of instructions that have been defined in  the method declaration.

Now there is one very important method that needs to be in all Java programs and this is known as the main method. This is important because when the program is run it searches for the main method. This is what a main method looks like.

public static void main(String [] args) {
….. //Code goes here}

Don’t worry about what this all means we haven’t got that far yet, but this is what a main method looks like

Bren

Java is an object oriented programing language (OOP), what this means (my understanding of it) is that it can organize data very well and lets people use this organised data and keep reusing it, therefore you can build on what you already have. This does seem useful as I’m sure we will be spending hours banging out code and it would be no good if we could not reuse what we have just written.

So what makes up object oriented programming? Objects (dah) and classes. So say you have a collection of cars, each car has doors, engine, windows, seats etc but for each car those things may differ slightly from each other, like color and size and wight, so each car here can be referred to as an object.  Even though these cars differ slightly in those aspects when you get to the core, they all have a door, an engine, windows etc etc so these characteristics are referred to as a class, sort of like a template.

The cool thing about this is that you can always refer back to the classes and objects that you have created, you can even inherit things from the classes that you make. For example if I created a Car class that defined the template for a car with doors, windows and engine size for example, and then i decide no wait, some cars come with added extra features, I could then create a class called Extras that inherits the Car class and all its features. Now in Java this is extending the class. So you could say that the class Car is the super class to the Extras class, soooo Extras extends Car. So another way of putting it is that the Car class is the parent class and the Extras class is the child class. Java lets you create more than one child class from the parent too, so say I now decide I need a performance class that has all the performance specs of all the cars, i can then create another class that extends the Car class(the super class or parent class) so I now have Performance extends Car. This means we now have two children of the parent Car class, which are Extras and Performance.

So far I have just told you about classes and objects which are at the core of Java as it is an OOP language, please let me know if you got questions or need more info so i can research it as well and post any other ideas and I will do the same.

Cheers for now…

Bren

I am using NetBeans 6.5 IDE and have updated my Java VM to the latest from Sun’s website, you can also download NetBeans IDE 6.5 from their too, they are both free so go ahead and download them.

You do not need to use NetBeans for your Java development, you can use any IDE that suites you, but by using NetBeans it will help as we will be using the same IDE as we go along and can help each other out with the IDE’s functionality. Check out Eclipse as well for another Java IDE.

I will post links just now as well for the download paths.

Bren

Right here is the link you will need, it is a bundled installation, it is NetBeans with the latest version of Java, get it

http://java.sun.com/javase/downloads/netbeans.html

I have created this blog to serve as a place to learn Java, including myself. I feel that this will help me and others who want to learn from scratch as the more heads  put together the more we can accomplish.

So if you are interested in learning Java and following me as we go along you are more than welcome to join and follow, there will aslo be help from some experienced Java developers that will pop in and help us as we go along, hope you have fun and welcome..

Bren