Introduction to Computers, the Internet and Java - Java: How to Program Early Objects - page 18

SE 8 Development Kit (JDK). See the Before You Begin section for information on down-
loading and installing the JDK on Windows, Linux and OS X.

Phase 1: Creating a Program
Phase 1 consists of editing a file with an editor program , normally known simply as an editor
(Fig. 1.6). Using the editor, you type a Java program (typically referred to as source code ),
make any necessary corrections and save it on a secondary storage device, such as your hard
drive. Java source code files are given a name ending with the .java extension , indicating
that the file contains Java source code.

Program is created in an
editor and stored on disk in
a file whose name ends
with .java

Phase 1: Edit Editor

Disk

Fig. 1.6 | Typical Java development environment—editing phase.

Two editors widely used on Linux systems are vi and emacs . Windows provides
Notepad . OS X provides TextEdit . Many freeware and shareware editors are also available
online, including Notepad++ ( notepad-plus-plus.org ), EditPlus ( www.editplus.com ),
TextPad ( www.textpad.com ) and jEdit ( www.jedit.org ).
Integrated development environments (IDEs) provide tools that support the soft-
ware development process, such as editors, debuggers for locating logic errors (errors that
cause programs to execute incorrectly) and more. There are many popular Java IDEs,
including:
• Eclipse ( www.eclipse.org )
•N t s ( www.netbeans.org )
• IntelliJ IDEA ( www.jetbrains.com )
On the topic's website at

www.deitel.com/books/jhtp10

we provide Dive-Into ® videos that show you how to executes this topic's Java applications
and how to develop new Java applications with Eclipse, NetBeans and IntelliJ IDEA.

Phase 2: Compiling a Java Program into Bytecodes
In Phase 2, you use the command javac (the Java compiler ) to compile a program
(Fig. 1.7). For example, to compile a program called Welcome.java , you'd type

javac Welcome.java

in your system's command window (i.e., the Command Prompt in Windows, the Terminal
application in OS X) or a Linux shell (also called Terminal in some versions of Linux). If
the program compiles, the compiler produces a .class file called Welcome.class that
contains the compiled version. IDEs typically provide a menu item, such as Build or Make ,
that invokes the javac command for you. If the compiler detects errors, you'll need to go
back to Phase 1 and correct them. In Chapter 2, we'll say more about the kinds of errors
the compiler can detect.