How do I run a .JAR file via the terminal

Question

Mispelled classname in manifest.txt file caused this error

Im trying to run a java file outside of my IDE by exporting the .jar file to my documents folder and trying to display the text 'hello world'in the file on the terminal line. I attempted to create a Manifest.txt file with this in it,

Main-Class: lightning.java.hello.MyFirstClass

I then used this script to create a file MyJar.jar and got this back,

lightning@rigel5:~$ jar cfm MyJar.jar Manifest.txt lightning.java.hello/*.class java.io.FileNotFoundException: Manifest.txt (No such file or directory) at java.io.FileInputStream.open(Native Method) at java.io.FileInputStream.(FileInputStream.java:138) at java.io.FileInputStream.(FileInputStream.java:97) at sun.tools.jar.Main.run(Main.java:171) at sun.tools.jar.Main.main(Main.java:1177)

Solution 1

You can run java package using this command on your terminal:

java -jar MyFirstClass.jar

If you don't have Java Runtime Edition (JRE) you'll need to install default-jre package.

Solution 2

First you need a main-method in your class file - public static void main(String args[]){ ... } - probably done...

In the jar-file you need a manifest.txt file - inside the class with the main method has to be noted like this -> Main-Class: MyPackage.MyClass

To create one you can use the commandline tool jar ...

If you don't have an manifest-file in your jar, you can just type:

java -cp jarFileName.jar ClassNameWithMainMethod

Solution 3

java /home/lighting/Documents/temp.jar Error: Could not find or load main class .home.lighting.Documents.temp.jar lightning

This shows that you clearly have done a mistake in the META-INF/MANIFEST.MF

See this Tutorial for more informations.

Comments

[AliN]

I couldn’t get your question. Do you mean a command to open a jar file? It’s java -jar path-to-file.

[Jaiden Fahey]

yeah Im trying to export a .jar file to the terminal line

[Jaiden Fahey]

lightning@rigel5:~$ java /home/lighting/Documents/temp.jar Error: Could not find or load main class .home.lighting.Documents.temp.jar lightning@rigel5:~$

[Jaiden Fahey]

at least I thought I did. how do I do that?

[Jaiden Fahey]

'clearly' never sounded better. will have a look :D

[Jaiden Fahey]

when I create the manifest file where do I put it?

[H.-Dirk Schmitt]

see the -m option for the jar command

[Jaiden Fahey]

lightning@rigel5:~$ java -cp temp.jar.lightning.java.hello.MyFirstClass I typed this in and got a java command usage index and did not display the file

[Jaiden Fahey]

See oracle.com/technetwork/java/javase/documentation/index.html for more details. lightning@rigel5:~$ java -cp temp.jar MyFirstClass.lightning.java.hello Error: Could not find or load main class MyFirstClass.lightning.java.hello lightning@rigel5:~$

[Jaiden Fahey]

lightning@rigel5:~$ java -jar MyFirstClass.jar Error: Unable to access jarfile MyFirstClass.jar lightning@rigel5:~$

[Jaiden Fahey]

this is my MANIFEST.MN file;Manifest-Version: 1.0 Class-Path: . Main-Class: lightning.java.hello.MyFirstClass I created a file Manifest.txt and it looks like this;MainClass: lightning.java.hello.MyFirstCLass

[Jaiden Fahey]

lightning@rigel5:~$ java -jar MyFirstClass.jar Error: Unable to access jarfile MyFirstClass.jar lightning@rigel5:~$ temp.jar lightning.java.hello.MyFirstClass temp.jar: command not found

[Muhammad Sholihin]

it seems you are on the wrong path, because it can not find the jar file. make sure you are in the jar file directory when using the command.

[Jaiden Fahey]

I had mispelled the classname in the manifest file. the classname is MyFirstClass not 'MyFirstCLass'. Oh, so embarrassed