How to run a JAR file

Question

I created a JAR file like this:

jar cf Predit.jar *.*

I ran this JAR file by double clicking on it (it didn\'t work). So I ran it from the

Answer 1

Java

class Hello{
   public static void main(String [] args){
    System.out.println("Hello Shahid");
   }
}

manifest.mf

Manifest-version: 1.0
Main-Class: Hello

On command Line:

$ jar cfm HelloMss.jar  manifest.mf Hello.class 
$ java -jar HelloMss.jar

Output:

Hello Shahid

Answer 2

Before run the jar check Main-Class: classname is available or not in MANIFEST.MF file. MANIFEST.MF is present in jar.

java -jar filename.jar

Answer 3

You need to specify a Main-Class in the jar file manifest.

Oracle's tutorial contains a complete demonstration, but here's another one from scratch. You need two files:

Test.java:

public class Test
{
    public static void main(String[] args)
    {
        System.out.println("Hello world");
    }
}

manifest.mf:

Manifest-version: 1.0
Main-Class: Test

Note that the text file must end with a new line or carriage return. The last line will not be parsed properly if it does not end with a new line or carriage return.

Then run:

javac Test.java
jar cfm test.jar manifest.mf Test.class
java -jar test.jar

Output:

Hello world

Answer 4

If you don't want to deal with those details, you can also use the export jar assistants from Eclipse or NetBeans.

Answer 5

I have this folder structure:

D:\JavaProjects\OlivePressApp\com\lynda\olivepress\Main.class D:\JavaProjects\OlivePressApp\com\lynda\olivepress\press\OlivePress.class D:\JavaProjects\OlivePressApp\com\lynda\olivepress\olives\Kalamata.class D:\JavaProjects\OlivePressApp\com\lynda\olivepress\olives\Ligurian.class D:\JavaProjects\OlivePressApp\com\lynda\olivepress\olives\Olive.class

Main.class is in package com.lynda.olivepress

There are two other packages:

com.lynda.olivepress.press

com.lynda.olivepress.olive

1) Create a file named "Manifest.txt" with Two Lines, First with Main-Class and a Second Empty Line.

Main-Class: com.lynda.olivepress.Main

D:\JavaProjects\OlivePressApp\ Manifest.txt

2) Create JAR with Manifest and Main-Class Entry Point

D:\JavaProjects\OlivePressApp>jar cfm OlivePressApp.jar Manifest.txt com/lynda/olivepress/Main.class com/lynda/olivepress/*

3) Run JAR

java -jar OlivePressApp.jar

Note: com/lynda/olivepress/* means including the other two packages mentioned above, before point 1)

Answer 6

A very simple approach to create .class, .jar file.

Executing the jar file. No need to worry too much about manifest file. Make it simple and elgant.

Java sample Hello World Program

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello World");
    }
}

Compiling the class file

javac HelloWorld.java

Creating the jar file

jar cvfe HelloWorld.jar HelloWorld HelloWorld.class

or

jar cvfe HelloWorld.jar HelloWorld *.class

Running the jar file

 java -jar HelloWorld.jar

Or

java -cp HelloWorld.jar HelloWorld