java script

Develop programs more quickly: The Java programming language is simpler than C++, and as such, your development time could be up to twice as fast when writing in it. Your programs will also require fewer lines of code.

Avoid platform dependencies: You can keep your program portable by avoiding the use of libraries written in other languages.

Write once, run anywhere: Because applications written in the Java programming language are compiled into machine-independent bytecodes, they run consistently on any Java platform.

Distribute software more easily: With Java Web Start software, users will be able to launch your applications with a single click of the mouse. An automatic version check at startup ensures that users are always up to date with the latest version of your software.

How things work in Java

You write the actual code for your programmes in a text editor. (In NetBeans, there's a special area for you to write code.) The code is called source code, and is saved with the file extension .java. A programme called Javac is then used to turn the source code into Java Byte Code. This is known as compiling. After Javac has finished compiling the Java Byte Code, it creates a new file with the extension .class. (At least, it does if no errors are detected.) Once the class file has been created, it can be run on the Java Virtual Machine. So:

Create source code with the extension .java

Use Javac to create (compile) a file ending in .class

Run the compiled class

NetBeans handles all the creating and compiling for you. Behind the scenes, though, it takes your sources code and creates the java file. It will launch Javac and compile the class file. NetBeans can then run your programme inside its own software. This saves you the hassle of opening up a terminal window and typing long strings of commands,

Now that you have a general idea of how Java works, launch your NetBeans software. Then click the link below to go to continue with the lesson

The Netbeans Software

When you first run NetBeans, you'll see a screen something like this one:

To start a new project, click on File > New Project from the NetBeans menu at the top. You'll see the following dialogue box appear:

You'll see the following dialogue box appear:

We're going to be create a Java Application, so select Java under Categories, and then Java Application under Projects. Click the Next button at the bottom to go to step two:

In the Project Name area at the top, type a Name for your Project. Notice how the text at the bottom changes to match your project name (in the text box to the right of Create Main Class):

firstproject.Main

If we leave it like that, the Class will have the name Main. Change it to FirstProject:

Now, the Class created will be called FirstProject, with a capital "F", capital "P". The package is also called firstproject, but with a lowercase "f" and lowercase "j".

The default location to save your projects appears in the Project Location text box. You can change this, if you prefer. NetBeans will also create a folder with your project name, in the same location. Click the Finish button and NetBeans will go to work creating all the necessary files for you.

When NetBeans returns you to the IDE, have a look at the Projects area in the top left of the screen (if you can't see this, click Window > Projects from the menu bar at the top of the software):

This same source code should be displayed to the right, in the large text area. It will be called FirstProject.java. If you can't see a code window, simply double click FirstProject.java in your Projects window above. The code will appear, ready for you to start work.

The coding window that appears should look like this (we've changed the author's name):

One thing to note here is that the class is called FirstProject:

public class FirstProject {

This is the same name as the java source file in the project window: FirstProject.java. When you run your programmes, the compiler demands that the source file and the class name match. So if your .java file is called firstProject but the class is called FirstProject then you'll get an error on compile. And all because the first one is lowercase "f" and the second one uppercase.

Note that although we've also called the package firsproject, this is not necessary. We could have called the package someprogramme. So the name of the package doesn't have to be the same as the java source file, or the class in the source file: it's just the name of the java source file and the name of the class that must match.

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 yan po ang pinag aaralan ni author .. busy busy han muna ko :)

lyn seuk won