Java Reference
In-Depth Information
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public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}
1.3.3
Building the project
Now that your class is finished, you can build the project.
Building
, in this case,
involves compiling the Java source into a class file, but the task can be a much
more complicated, multistage process for complex Java projects. Follow these
steps to build your project:
Select the
Build | Make Project
menu option (or, if you prefer, click the
Make Project
button on the toolbar, or use the keyboard shortcut
Ctrl+F9
).
1
Because this is the first time you're building the project,
IDEA
recognizes
that the directory where the compiler's output classes should go doesn't
yet exist. Click
Ye s
to let
IDEA
create the output directory for you.
2
That's it! If you navigate your file system and look in that output directory, you'll
find a directory structure that matches the package structure in the
Project
tool
window, and the
HelloWorld.class
in the
com.acme.helloworld
package.
1.3.4
Running the project
HelloWorld
is a special Java class in that it has a
main()
method, an entry point
that marks this class as a command-line executable. Consequently, you can
directly run and test this class to ensure its behavior operates as expected. Follow
these steps to run your class:
Select the
Run | Edit Configurations
menu option.
1
The
Run/Debug Configurations
window appears, allowing you to man-
age the different ways to execute and test code that you write. This sam-
ple is a simple Java application, so ensure that the
Application
tab is
selected. If it isn't, click it.
2
Click the plus button (
+
) to create a new Java application run configura-
tion. A new configuration is immediately added with the title Unnamed.
3
