Java The Beginning

Why Java?  Currently, this is the language of the international AP course which runs Feb-Apr  FREE!  Platform-independent  Simple to learn but powerful  Used in Flash Actionscript  Used in Android programming

What can Java do? Java can be used to develop many types of applications. Java Applications are standalone programs that run on the desktop. They can be:  Console apps  simple, text-based programs that support text IO to the monitor  GUI apps  can have menus, toolbars, buttons, etc. Applets run in a browser and easily shared over the Internet.

Java Applet In Jcreator, create a new workspace named Applets. Save your applets into this workspace. Each new applet will be a new project. Create a new Basic Java Applet. Replace all the code in it with the code from below. Note the corresponding htm file that is created for you, saving you creating it manually.

 Java filenames must match the class name exactly.  Java is case-sensitive  Java code is compiled, creating a file with the. class extension. You can see this file in windows explorer.  Applets run through a browser, and therefore require an htm file. JCreator will create this for you, or you can create one manually.  New security on java apps has made browser testing difficult. JCreator features an applet viewer making testing easier.

Libraries  A library is a collection of useful classes.  Use the import statement to make a library available to your program.  You will use several libraries in this course, such as java.awt and javax.swing.

Structure of a Java Program  Java programs are made up of a number files called classes, each one performing a specific task.  One class in the program will contain the main() method, which the computer searches for to get things running.  An applet will have a paint() method that is called automatically when it is started.  Inside of a class we have methods and instance variables.

Naming Conventions  Classes are named in TitleCase  Methods are named in camelCase and always have ()  Variables are named in camelCase  Constants (aka finals ) are UPPER-CASE.

Java Help  The best help for java is the java api on the Internet. Try  Look up the drawString method api.

Close your workspace, and create a new Blank Workspace for Applications. Add a New Project named HelloWorld. It will come up similar to below. Alter yours to match this and make sure it compiles and runs.

Close your workspace, and create a new Blank Workspace for GUI-Apps. Add a New Project named HelloWorldGUI. It will come up similar to below. Alter yours to match this and make sure it compiles and runs.

An Applet with Graphics  Close your workspace and open the Applet workspace.  Add a new applet project named ShapesAndColors. The api can give you more information on possible graphics methods that you may use to create a unique image.

Work on Lab 01D – Robot. All required files are on the shared drive.