Mac Java! • Tutorial: How to create a Mac OS X installer for a Java application (.jar)

How to Create a Mac OS X Installer for a Java Application
(Updated for Mac OS X 10.7 — Lion)

This information is for an older version of Mac OS X.
For more current information, visit: Mac Java

With some simple steps you can turn your Java Swing program (.jar) into a proper Mac OS X application with a native installer. The instructions below step you through the process from scratch with a sample program called "Show Time", which simply displays the current time. Once you have successfully completed the tutorial with the sample Java program, modify the steps to work for your Java program.

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1) Launch Unix Terminal and Get Java

Using "Finder" go into "Applications" and then open the "Utilities" folder. Scroll down until you see "Terminal". Open "Terminal" and you're now at the Unix prompt. Enter the following command to see if you already have Java installed:

java -version

You will be prompted to download and install Java if needed.

2) Make Project Folder

At the Unix prompt, enter these two commands:

mkdir showtime
cd showtime

The first command creates a folder called "showtime", and the second command moves you into the new folder.

3) Write Some Java Code

Mac OS X comes with a simple but effective text editor called Pico. Use the following command to create and edit a new Java file:

pico ShowTime.java

Enter the following code:

ShowTime.java

import java.util.Calendar; import javax.swing.*; public class ShowTime { public static void main(String[] args) { JFrame f = new JFrame(); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setTitle("It's Showtime!"); f.getContentPane().add(new JLabel( Calendar.getInstance().getTime().toString())); f.pack(); f.setVisible(true); } }

view/download code

Use <control-x> to exit Pico.

4) Compile Java Program

Back at the Unix prompt, compile the Java program into a class file:

javac ShowTime.java
ls -l

We could run the class file directly, but a class file is cumbersome. Instead we will create an executable JAR file.

5) Make Executable JAR

Before we make an executable JAR file, we need a manifest file to indicate which class contains the "main" function. We'll use Pico again:

pico MainClass.txt

Our manifest file will only have one line:

MainClass.txt

Main-Class: ShowTime

Exit Pico and use the following "jar" command to create the "ShowTime.jar" file:

jar cmf MainClass.txt ShowTime.jar *.class
ls -l

Now test your executable JAR with the following command:

java -jar ShowTime.jar

The "It's Showtime!" window with the current time should display in the upper left corner of the screen. Click the red button (marble) to exit the program.

While the manual commands above for steps #4 and #5 work fine, you could automate them using Ant with this build.xml file.

6) Install Xcode

Apple's Xcode suite includes the developer tools you'll need to create an icon and an installer. Go to the Mac App Store and install Xcode.

7) Create Application Icon

The default icon for an executable JAR is a coffee cup. To add a custom icon, we need to use the "Icon Composer".

Download and save (<control-click>) this sample PNG image to your "Desktop": ShowTime.png

Then move the file into the "showtime" folder with the "mv" command:

mv ../Desktop/ShowTime.png .
ls -l

Now we can create the icon file.

Steps:

Use "Finder" to navigate into the "/Developer/Applications/Utilities" folder and double-click "Icon Composer".
Go back to "Finder" and navigate to your "showtime" folder (which is in your home folder).
Drag the "ShowTime.png image file into the "128" box on the "Icon Composer" screen.
Go into the "File" menu and select the "Save" option.
Click the down triangle button to show the file navigation options and navigate to the "showtime" folder.
Deselect the "Hide extension" option and save as "ShowTime.icns".
Quit "IconComposer".

With our new icon, we can now create a Mac application.

8) Bundle the JAR

Bring up Spotlight with the <command-space> keystroke and type "jar bundler" to find and the "Jar Bundler" application (it's in the "/usr/share/java/Tools" folder). Launch the application.

Steps:

For the "Main Class:", use the "Choose..." button and go to and choose "ShowTime.jar".
Check the "Use Macintosh Menu Bar" option.
Use the "Choose Icon..." button to choose the "ShowTime.icns" file (you'll need to navigate to the very top-level folder and then into the "Users" folder and your home folder to eventually find the "showtime" folder).
Click the "Properties" tab and enter "1.0" into the "Version:" field.
Also enter "1.0" into the "Get-Info String:" filed.
Click the "Create Application..." button.
Navigate into the "showtime" folder.
In the "File:" field, enter "Show Time".
Click the "Create" button.
Quit "Jar Bundler".

We now have a proper Mac application. Next we'll create an installer for the application.

9) Create Mac Installer

Using "Finder", navigate into the "/Developer/Applications/Utilities" folder and double-click "PackageMaker".

Steps:

In the "Organization:" field on the "Install Properties" window, enter "com.centerkey". Then click "OK".
Click the "Configuration" tab, and in the "Title:" field enter "Show Time".
Go to the "Project" menu and select "Add Contents...". Navigate to the "showtime" folder and then select and choose "Show Time".
Deselect "Allow Relocation" (to prevent the verion you are building from being confused with the installed version).
Click the "Contents" tab. Check the "Include root in package" option and click the "Apply Recommendations" button.
Now click the "Build" (hammer) button. In the "Save As:" field, enter "ShowTimeInstaller.pkg". Click the "Save" button and then the "Return" button.
Go to the "File" menu and select "Save". In the "Save As:" field, enter "ShowTime.pmdoc" and then click "Save".
Quit "PackageMaker".

Our installer is done, but it's not yet download friendly.

10) Put Installer on a Web Page

Before putting the installer on the web, we need to zip it up into a single file. Use "Finder" to navigate to the "showtime" folder. Create a zip of "ShowTimeInstaller.pkg" using the "Compress" option on the <control-click> menu.

Back at the Unix prompt in the "Terminal", create a test web page:

pico download.html

The HTML for the test page is:

download.html

<html> <body> Download: <a href=ShowTimeInstaller.pkg.zip> ShowTimeInstaller.pkg.zip</a> </body> </html>

After exiting Pico and saving the web page (.html) file, copy it and the .zip file to your personal web server folder with the command:

cp *.html *.zip ../Sites

Now we need to turn on the Mac's Apache web server.

Steps:

Go to the "Apple" menu () and choose "System Preferences...".
In the "Internet & Wireless" section, click "Sharing".
Check the option for "Web Sharing" service.
Quit "System Preferences".

Your Apache web server is now running.

Launch Safari and go to http://localhost/~you/download.html where "you" is your user name. Click the "ShowTimeInstaller.pkg.zip" link. If the install does not start automatically, go into your "Download" folder and double-click the file. After completing the installation, go into the "Applications" folder and run the "Show Time" application. Be sure to check out the "About Show Time" option on the "Show Time" menu.

Troubleshooting

If your application does not install and run properly, the first place to look is step 5, which creates the JAR file. Try double-clicking the JAR file to launch your application. If it fails to launch, you need to fix that before continuing.

The next place to look is step 7, which creates the application file. Try double-clicking the .app file. If it fails to launch, you need to fix that before continuing.

Do the same for step 9, which creates the installer file (.pkg).