I have the following Java file(apples.java):
public class apples
{
public static void main(String[] args)
{
System.out.println("Apples here.");
}
}
saved in the source folder of the MyProject directory.
I compile apples.java and save the apples.class file into the classes folder of the MyProject directory.
I then create manifest.txt with the following content:
Main-Class: apples
I then navigate into the MyProject/classes directory via cmd prompt(Windows XP) and type the following command:
jar -cvmf manifest.txt app1.jar apples.class
I get the following message in the command prompt:
java.io.FileNotFoundException: manifest.txt (The system cannot find the file specified)
at java.io.FileInputStream.open(Native Method)
What is wrong and how do I fix it?
Put the .jar argument first
jar -cvmf app1.jar manifest.txt apples.class
Make sure both "apples.class" and "manifest.jar" are in the current directory.
I would also encourage you to:
1) Use packages (instead of the default package)
2) Capitalize your class names ("Apples.java" instead of "apples")
Here's a nice, short tutorial that might help:
http://www.mkyong.com/java/how-to-add-your-manifest-into-a-jar-file/
It is a common mistake people make. While creating the manifest.txt, make sure that you don't name it "manifest.txt", after you've already selected the file to be a txt. That makes it "manifest.txt.txt". Hope it helps.
Related
I need help getting a file from a file to use it.
The file is specified in the -cp option when running jar through the console.
run the jar using:
java -cp myjar.jar:dir1/dir2/myfile.txt com.company.Main
execution result:
Exception in thread "main" java.lang.NullPointerException
at com.company.Main.main(Main.java:11)
source code:
package com.company;
import java.io.InputStream;
public class Main {
public static void main(String[] args) {
ClassLoader classLoader = Main.class.getClassLoader();
InputStream resource = classLoader.getResourceAsStream("dir1/dir2/myfile.txt");
System.out.println(resource.toString());
}
}
project tree
-- сom
---- company
------ Main.java
How do I get that file from -cp?
Since you specify dir1/dir2/myfile.txt in the getResourceAsStream() call, you want the directory containing dir1 on the classpath, which would be the working directory, i.e. .:
java -cp myjar.jar:. com.company.Main
The classpath can only specify:
Directories
Jar files
No other type of file is supported.
It appears that your computer cannot find the file. Right click on the file and select explorer to see the path or if you are using intellij idea you will see an option to copy the path when you right click on it.
I'm trying to create a jar file and run it using java -cp main.jar com.test.Foo.Main but I keep getting:
Error: Could not find or load main class com.test.Foo.Main
Caused by: java.lang.ClassNotFoundException: com.test.Foo.Main
This is my file structure. So I'm thinking the line in my Main.java should be package com.test.Foo correct?
I'm compiling my Main.java with javac Main.java which outputs a Main.class file. Afterward, I create a jar file using jar cfm main.jar META-INF/MANIFEST.MF Main.class and finally while I'm in the same directory as the jar file <root>/src/com/test/Foo/ I run java -cp main.jar com.test.Foo.Main and that's when I run into the above error. Any idea how I can run this file like this (and yes I need it to run with this command specifically)?
Main.java
package com.test.Foo;
public class Main {
public static void main (String args[]) {
System.out.println("I am com.test.Foo.Main");
}
}
META-INF/MANIFEST.MF
Manifest-Version: 1.0
Main-Class: com.test.Foo.Main
I tried using some of the options given in this popular SO question and nothing helped.
The picture you're showing in your question is your project structure not your jar structure.
When you create a jar file, the structure for that jar file might be
different with your source code folder structure.
Every IDE (such as eclipse, netbeans, IntelliJ) has a mechanism for creating JAR files. In your case when you open the created jar file (using zip apps like winrar) you should see something like this :
com
|
test
|
Foo
|
Main
META-INF
|
MANIFEST.MF
This should be the ordering of your files and folders, otherwise Java can not find your main class from MANIFEST.MF
Now to solve this problem:
Open your jar file using a zip application like winrar
check the folder structure residing inside your jar file as I draw
Fix it right away within the winrar or try to correct your project structure to produce the structure I mentioned.
The class is called com.test.Foo.Main you need to specify the full name in the command:
java -cp main.jar com.test.Foo.Main
or you can use the simpler
java -jar main.jar
Check your META-INF/MANIFEST.MF for the attribute of Manifest-Version: 1.0
This attribute must be there.
Edit:
You need to move to the source root src/ and issue below command to create a valid jar.
javac com/test/Foo/*.java
and, create the jar using,
jar cmf com/test/Foo/MANIFEST.MF main.jar com/test/Foo/*.class
The thing is, package structure should match with the folder structure apparently.
Been looking for around 2 hours for a solution to my problem, tried countless solutions and still the problem remains unsolved.
I have a game project with few packages; geometry, levels, decoration, and game. Inside the game package resides a gameRun.java
package game;
public class gameRun {
/**
* Program entry point.
* #param args the arguments for the levels
*/
public static void main(String args[]) {
... some code
}
}
and I have the following manifest file :
Main-Class: game.gameRun
Class-Path: someExternalGraphicTool.jar
//newline here
I compile my whole game using the following command : (the bin folder already exists).
javac -d bin src/geometry/*.java src/decoration/*.java src/levels/*.java src/game/*.java
I then turn my compiled classes into an executable .jar file using the command :
jar cvfm t.jar manifest.mf bin/geometry/*.class bin/decoration/*.class bin/levels/*.class bin/game/*.class
I then try to run my t.jar using :
java -jar t.jar
//or
java -cp .:t.jar game.gameRun
which both produce the error, "Error: Could not find or load main class game.gameRun"
However, when I unzip the jar file, inside the bin/game directory I can see a gameRun.class file and inside the META-INF\MANIFEST.MF file I can still see that the Main-Class is set to game.gameRun.
Note that I am working on a remote linux server, on a command line, and the jar file doesn't work even if I download it to my windows 10 machine.
What did I do wrong during this process ? Thanks for any help.
Your classes are in a wrong structure inside a jar file, because of the bin folder. My suggestion: pack it all into a jar starting in a bin folder.
Now when you extract your jar you will see 2 folders: META-INF and bin.
If you make the jar from bin folder you will see: META-INF and game, and it will work.
It doesn't work for you simply, because it can't find the main class, since it is inside the bin/game/YourClass.class, not in game/YourClass.class.
...\bin> jar cvfm t.jar manifest.mf geometry/*.class decoration/*.class levels/*.class game/*.class
And then just:
...\bin> java -jar t.jar
I'm trying to run a project from the command line (Ubuntu 14.04). The main class is called Demo, and I have a Demo.java, a Demo.class, and a Demo$1.class all in the same directory (I know it would be better to seperate them).
I wrote my own Manifest file, MANIFEST.MF, which just looks like this:
Main-Class:Demo
I made sure to end it with a newline.
Next, I want to create my .jar file. I did so with this command:
jar -cfm example.jar MANIFEST.MF *.class
Then, I try to run my project like so:
java -Djava.library.path=/path/to/dependencies -jar example.jar
I seem to get the following error no matter what I try:
Error: Could not find or load main class Demo
I've actually never compiled/run a Java project from the command line before, it's possible I'm making a stupid mistake and just can't figure it out. Any help is appreciated!
EDIT: Here are the contents of example.jar, according to vim:
" zip.vim version v27
" Browsing zipfile /home/ellen/bendersexample2/src/bendersexample/example.jar
" Select a file with cursor and press ENTER
META-INF/
META-INF/MANIFEST.MF
AnnotatedBenders.class
Demo$1.class
Demo.class
Demo$ModelType.class
ManualBenders$1.class
ManualBenders$BendersCallback.class
ManualBenders.class
Model.class
Problem.class
Solution.class
Solution$Verbosity.class
StandardModel.class
Here are the contents of the META-INF/MANIFEST.MF which is in the jar:
Manifest-Version: 1.0
Created-By: 1.8.0_161 (Oracle Corporation)
Main-Class: Demo
UPDATE: Here are the interesting parts of Demo.java:
package bendersexample;
public final class Demo {
/* Some functions */
public static void main(final String[] args) {
/* Some code */
}
}
I changed my MANIFEST.MF to the following:
Main-Class:bendersexample.Demo
And re-generated the example.jar file. I still get the following:
Error: Could not find or load main class bendersexample.Demo
Could there be an issue with how I generate my class files?
To generate the class files initially, I did the following:
javac -classpath .:/opt/ibm/ILOG/CPLEX_Studio_Community128/cplex/lib/cplex.jar *.java
Please let me know what else I should try! Thank you
The problem was just that had the Manifest in the /bendersexample folder and the was creating the .jar in this folder as well! I just needed to move that stuff into the parent directory and everything worked fine!
The final Manifest file used bendersexample.Demo as the Main-Class, and the jar was created and run from /bendersexample 's parent directory.
If anyone runs into this problem I would recommend taking a look at your project's structure before trying anything else, because this turned out to be a very easy fix!
I've been trying to run a app from a Jarfile, but it keeps printing out:
"cannot find or load main class ...".
I tried to solve this problem using infos from this thread but all seemed to be useless. To be honest, I'm getting desperate because of the fact that this is such a trivial problem.
Anyways, what I did:
Main-Class: com.test.Test
my manifest attribute:
jar cfm test.jar manifest.txt <full_path>/out/com/test/*.class
which is what's packaged into the jar file (the Test.class file)
The Test class:
package com.test;
public class Test {
public static void main(String[] args) {
System.out.println("Hello World");
}
}
You should package the class correctly. Do
jar cfm test.jar manifest.txt com/test/*.class
in the parent folder of the folder com. By providing the absolute path (the way you did), the class file is packaged incorrectly.
Firstly, just in case you are using Eclipse IDE, there is some tools like the Fat Jar Plugin which are able to help you to package your build.
Secondly, there is Maven, to handle your dependencies, and build the package you need with everything ok. In your case, I will look for the Apache Maven Jar Plugin.
Finally, the old school way to go with the commandline, as you tried to do.
As Eliott Frisch has said in your question comments, you don't need to provide the fullpath to the mainclass inside your jar cfm test.jar manifest.txt <full_path>/out/.
And what's because the manifest.txt already give the package information!