|What do you need to download?|
|Basics of Java
Java is an object oriented programming language. Think about a car. A car is made up of many objects such as wheels, pedals, engine, and many more. Similarly, a Java program contains objects that perform tasks collectively.
These objects are categorized as classes. For example two different cars can have a wheel that has the same properties. Thus, these two objects of wheels represent the same class, the class of a certain wheel object.
A Java file(.java) needs to be compiled to a .class file. ( IDEs do this automatically as you try to run a .java file. Otherwise you should compile a .java file from the command line by entering javac name.java in the directory where the file lies) Then the .class file is the one that is executed.( in IDEs automatically, for command line enter java name of the class file in the directory where the .class file lies)
In every Java file there can only be one main class (referred as public class) declaration and the name of the class and the .java file should be the same.
Java is CaSeSeNsItIVe
These are the most fundamentals. Now you can continue with the next section: Sample Projects
|First of all, all you need to download is completely free. The only required thing is the Java SE( standard edition ) Development Kit which enables you to write, compile and run your own Java programs. The latest edition is the 6th one at the moment. Here is the link:
JDK 6 Update 3 ( you may need to register)
Next, perhaps the thing you should consider is to download an IDE which enables to write, compile and run your programs easily. It even underlines the mistakes in your code which helps you to debug faster. Otherwise, you need to use a simple text editor and run your program from the command line.
There are three reasonable choices as an IDE.
Eclipse (I have not tried this one yet.)
Sun JavaStudioCreator is actually based on NetBeans (you may need to sign up in order to download)
Note: There is a great IDE called IntelliJ, but it is not for free.