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How to make a JAVA application - executable JAR archive:
This simple tutorial is based on the DiveLog example published by Sun.
Download these templates for an extremely simple application template.
If you know how to make an applet, you can easily make an application
with this template.
Save all files from below into a directory. (rename *.java.txt to *.java)
Create a batch file with the following content:
javac DiveLog.java
jar cvfm DiveLog.jar mymanifest DiveLog.class DiveLog$1.class DiveLog$2.class Welcome.class
If you're compiling this on a Linux system, you need to add backslashes before the dollar signs:
javac DiveLog.java
jar cvfm DiveLog.jar mymanifest DiveLog.class DiveLog\$1.class DiveLog\$2.class Welcome.class
Watch the line wrap: There are only 2 lines in the batch file, one starting
with javac and the other
with jar.
Run the batch file and it should compile the application and create DiveLog.jar, which can be
clicked in order to run it.
You can also run the application from the command line by typing:
java -jar DiveLog.jar
which does the same like clicking
on the icon of the application, but you can see any output written by
System.out.println("..."); or error messages.
DONE! :-) It's that easy! Now it's time to add something useful to the application. Port the code of your applet
to the application, or write something completely from scratch. Java applications are a really neat thing - the
JPL and NASA use tons of Java applications (yes, even the Mars Rovers are controlled with Java applications!)
For a more advanced example see: Java Application Template Tutorial
Executable Java Application Files Download:
Main class: DiveLog.java
The class which will be displayed in the JFrame: Welcome.java
The manifest file, which will define the main method for the application:
mymanifest
TROUBLESHOOTING:
QUESTION: When clicking the executable jar-archive an error window
appears! Whats wrong ?
Java Virtual Machine Launcher
Could not find the main class. Program will exit!
ANSWER:
1. The
Main-Class in the manifest is not defined / has the wrong classname.
A correct manifest looks like this:
Manifest-Version: 1.2
Main-Class: DiveLog
Created-By: 1.4 (Sun Microsystems Inc.)
The Main-Class in the manifest defines the class with the starting point
for the application:
In other words, it is the class with this line:
public static void main(String[] args)
2.
Make sure you added the Manifest to the JAR-archive:
Verify the archive with:
jar vft DiveLog.jar
There should be a line with META-INF/MANIFEST.MF
Extract the archive in a new directory with:
jar xvf DiveLog.jar
There should be a directory named META-INF. Verify the manifest in META-INF for it's correct syntax and content.
QUESTION: When running the app In the command line with java
-jar DiveLog.jar I see the following:
Exception in thread "main"
java.lang.NoClassDefFoundError: divelog/DiveLog
ANSWER:
1. Make sure you added the Manifest to the JAR-archive:
Verify the archive with:
jar vft DiveLog.jar
There should be a line with META-INF/MANIFEST.MF
Extract the archive in a new directory with:
jar xvf DiveLog.jar
There should be a directory named META-INF. Verify the manifest in META-INF for it's correct syntax and content.
2. The original example of the DiveLog at sun.com has a package declaration:
package divelog;
In my opinion this just complicates everything, therefore I deleted the
line in my example.
In order to compile the original DiveLog, you need to add a few things:
Assuming there is package divelog;
at the beginning of any java-file of the project and your files are located
in:
c:\java\divelog\ (note:
the name of the directory divelog is a must)
Go to c:\java\divelog\
and compile it with:
javac -classpath c:\java\ DiveLog.java
Go to c:\java\ and make the archive with:
jar cvfm DiveLog.jar mymanifest divelog\DiveLog.class divelog\DiveLog$1.class
divelog\DiveLog$2.class divelog\Welcome.class
Note: This is just one line!
The manifest looks like this (possibly you had that before, hence the error message):
Manifest-Version: 1.2
Main-Class: divelog.DiveLog
Created-By: 1.4 (Sun Microsystems Inc.)
But you see where this is going to: Much more hassle for the same effect!
Therefore I left out the package declaration!
Last-Modified: Tue, 27 Oct 2009 16:51:11 GMT
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