from bluej to netbeans
DESCRIPTION
From BlueJ to NetBeans. SWC 2.semester. Why change…?. BlueJ is great for introduction to programming Simple interface, few options Graphical interface to classes and objects Some tehnical details are hidden. Why change…?. NetBeans is great for professional programming - PowerPoint PPT PresentationTRANSCRIPT
Why change…?BlueJ is great for introduction to
programming◦Simple interface, few options◦Graphical interface to classes and
objects◦Some tehnical details are hidden
Why change…?NetBeans is great for professional
programming◦Much more functionality◦Better editor, debugger,…◦Integration to database systems◦A full-blown, stand-alone system
…but also more complex!
What is NetBeans?NetBeans is an open-source
projectOriginates from SUN
Microsystemswww.netbeans.orgCan - of course – be downloaded
for free from the websiteWe use NetBeans 6.9.1 SE (+
Java JDK)
How do I……create a new project?…add a new class?…edit a class definition?…write text to the screen?…get input from the user?…run a project?
Create a new project - NetBeansWhy is there a ”Main.java”
class…?All Java programs must contain a
method with this signature:public static void main(String[] args)
This was hidden in BlueJ!Think of Main as a ”System”
classWhen the program starts, the
code in the main(…) method is executed
Edit a class definition - NetBeansWhy do red lines start to appear
in the code, as soon as I start typing…?
The NetBeans editor continuously makes an analysis of the code, even before it is compiled
The editor highlights errors in the code by a waved red line, even before typing has been completed
Helpful…? Annoying…?
Edit a class definition - NetBeansWhy do lists with method names
pop up when I type…?The NetBeans editor supports
”auto-completion”, i.e. it tries to predict what you will type next
Typically when calling a method with ”.”
Helpful, when you get used to it…
Edit a class definition - NetBeans
Available methods on the specific object/class
Documentation for each method
Get input from the user - NetBeansNot quite as simple to get input
from a user in NetBeansTwo options
◦Use the Scanner class◦Use a input dialog class
See chapter 3.6 in Big Java for details
Get input from the user - NetBeansimport java.util.Scanner;…Scanner in = new Scanner(System.in);…String name = in.nextLine();…int balance = in.nextInt();…double area = in.nextDouble();
Get input from the user - NetBeansimport javax.swing.JOptionPane;…String value = JOptionPane.showInputDialog(”Limit”);
…int limit = Int.parseInt(value);
Running a project - BlueJWe cannot as such ”run” a
project in BlueJ – what should run..?
We usually create a ”system” class, that has a ”run”-like method◦Create a System object◦Right-click the object◦Call the run method
Running a project - NetBeansRunning a project always
executes the main method in the Main class!
A project is automatically compiled when you save it
No reason to run a project in order to fix syntax errors