Question

I created a program that more or less holds an array of strings as an object and randomly prints one.

so basicaly

class Fun 
{


       string[] namestrings = new string[#] 

       constructor() 
       { fill with some strings} 

       public static void main (String[]arg) 
       { 
            create instance of class
            do some junk with it 
            method that prints it 
       } 
       method that prints it {} 
       another method 
    } 

when i compile and run it on the command line it works fine but when on the comand line i type in jar -cf Happy.jar Fun.class


i get a .jar file called Happy and when i click on it i get an error message that reads “the java Jar file happy could not be launched read the consol for possible error messages” I have a mac i’m running lepord if that makes a diference. Whats going on?

Answer 1

Have a manifest.mf with following content, and pack it to your JAR file as META-INF/manifest.mf

Manifest-Version: 1.0
Ant-Version: Apache Ant 1.7.1
Created-By: 14.3-b01 (Sun Microsystems Inc.)
Main-Class: Fun

You may then execute your application using

java -jar Happy.jar

IDE will usually do that automatically for you, if you create your project as Java Application.