In Intellij, I'm able to "build an artifact" which allows me to create a jar file, even though my project uses other jar files (like drivers). Traditionally, I would compile a project with jar dependencies by putting them in my classpath like so:
javac -cp .:dependency.jar Main.java
and then be able to run Main by doing:
java -cp .:dependency.jar Main
My question is, how do I create a jar file file with this new Main? I can do:
jar cvf Main.jar Main.java
which will create a jar file, but it doesn't run and says:
no main manifest attribute, in Main.jar
I'd like to know how to package my other jar dependencies into on executable jar.
Option 1: Using Maven plug-in if you are using maven:
<plugin>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>Path.to.your.main.class</mainClass>
<addClasspath>true</addClasspath>
</manifest>
</archive>
</configuration>
</plugin>
Option 2: Using spring boot to create fat jar. Which includes all your dependent jar files. Make sure you include spring boot dependency.
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>1.3.3.RELEASE</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
Option 3: Without any help of maven and Spring:
Create a manifest.txt file with the following content:
Main-Class: path.to.your.main.class
To create jar use command : jar -cvfm Application.jar manifest.txt /path/to/*.class
Related
I have a java program that I coded in intellij using maven. I exported it as a jar and tried running from the command line but it keeps on telling me
Error: Could not find or load main class com.company.Main
Caused by: java.lang.ClassNotFoundException: com.company.Main
I then attempted to run the program itself from the command line and that also tells me it cannot find the main class
command line:
for the jar: java -jar selenium_project.jar
for running the program :java com.company.Main
For the jar I am running it from the folder it is in. For the program I am running it from the root of the program.
Pom.xml
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.4</version>
<configuration>
<archive>
<index>true</index>
<manifest>
<mainClass>com.company.Main</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
</plugins></build>
Manifest:
Manifest-Version: 1.0
Main-Class: com.company.Main
It might be an issue with maven, I dont know. I created a simple hello world program and ran that from the command line and it worked. I ran it like this (c://etc)../src/> java com.company.HelloWorld. But again when i try for this one it cannot find the main class.
Thank you
These are my classes
EDIT:
I changed to use the maven-assembly-plugin and I rebuilt the jar and still does not work
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
<configuration>
<archive>
<manifest>
<mainClass>
com.company.Main
</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</execution>
</executions>
</plugin>
</plugins></build>
class structure to show where main class is
code in the Main class
public class Main {
public static void main(String[] args) throws IOException, SQLException {
System.out.println("hello");
Executor ex = new Executor();
}
}
Your error is probably that your Main class is in the wrong package.
Furthermore, please not that you need the Maven shade plugin or Maven assembly plugin to build executable jars if you have dependencies.
I dont know what the issue was. I tried creating a new program and i copied over the classes and remade the pom.xml file and my new program works except for one dependency (chrome options) but I dont think that is what was causing an issue. So now I just need to figure out why Chrome options wont work but the actual jar from the new program does run.
From： https://www.xspdf.com/resolution/54971948.html
To extract the files from a jar file, use x , as in: C:\Java> jar xf myFile.jar. To extract only certain files from a jar file, supply their Install an archive program. JAR files work just like ZIP files. You can use any archive program to extract them. 2. Find the JAR file you want to extract. Use File Explorer (press Win + E to open File Explorer) or Finder on Mac to 3. Right-click the JAR file. Doing so . How to extract manifest file from jar. Extracting the Contents of a JAR File.
So I worked on a project and i coded everything in eclipse. I had my codes in folder called src and my libraries in a folder called lib. The problem is that, my code needs to be excecuted in the terminal. Well, now i get tons of errors. All of them are because there are libraries missing. I tried to import the .jar file from the lib folder to the src folder but the code still didn't work.
So, how can I "install" the libraries in the terminal?
btw. the library I'm trying to install is the com.google. I've already cloned it with the following line:
git clone https://github.com/google/gson
First of all, you have to make your project to compile perfectly with your IDE or whatever.
Later, you should create the runnable JAR file (with eclipse if you want, but it's important the world RUNNABLE jar file. Click in your project > Export > runnable jar file and select you main class in "Launch configuration".).
Finally, go to the console to the path of your JAR file and execute
java -jar file.jar
I think it should work :)
If you want to build your project from terminal, you need to make sure of two things.
1. You should have main class attribute in mainfest file.
2. Jar should be compiled with all the dependencies. (This will result in a bigger jar though)
You can do both with maven assembly plugin. Add the following in build/plugins in your pom.xml
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>com.tanmayvijayvargiya.MainApp</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
Update the with your mainClass
To build the jar, run mvn package. This will generate jar in your target folder.
Next, to run the jar run java -jar target/jar-name-with-dependencies.jar
Source
Maven Assembly Plugin Usage
I am working in Java Maven project. There is a .bat file in the root of the project which invokes a Java class with some arguments something like this:
java my.package.MyClass abc hi 1
Now, my project jar is built in the target directory of that project when I do mvn clean install. When I run that .bat file it gives me the below error
Error: Could not find or load main class my.package.MyClass
Project's pom.xml only contains jars as dependency.
Do I need to do something in pom.xml to make it work?
please provide your pom.xml so we can look for it,
anyway,
do you use maven-jar-plugin?
something like this
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.4</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>lib/</classpathPrefix>
<mainClass>your.main.class.package.ClassName</mainClass> // your main class
</manifest>
</archive>
</configuration>
</plugin>
and try to run your *.jar with command java -jar yourjar.jar
A very noob question.
I have a java class
package org.foobar;
import thirdparty_jar1;
import thirdparty_jar2;
public class FooBar{
public static void main(String[] args){
// some code
}
}
I use eclipse as my ide and I added these thirdparty jar 1 and jar 2 in its build path. and then I proceeded to export the jar.
Now I have a foobar.jar file and now I want to run it..
I did java -cp /path/to/foobar.jar org.foobar.FooBar
but it complains about missing third party libraries.
How do i run my jar (or probably build a fat jar) . I just want to run my program from command line.
Thanks
A jar has a manifest file called MANIFEST.MF, under the folder META-INF. This contains details about the jar file, the main class etc. Eclipse creates one by default, you can modify that or specify your own manifest file.
See http://docs.oracle.com/javase/tutorial/deployment/jar/manifestindex.html and Understanding the Default Manifest.
To add libraries to the classpath, you need to add the jar files' path to the manifest file, like this:
Class-Path: jar1-name jar2-name directory-name/jar3-name
See Adding Classes to the JAR File's Classpath
If you're using Maven, you can add this to your pom.xml file. This will create an additional "fat" jar whenever you build with Maven. It goes in the 'build.plugins' section:
<build>
<plugins>
...
<!--
The plugin below creates an additional, executable JAR with all dependencies
included in it.
-->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.4</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>attached</goal>
</goals>
</execution>
</executions>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
<archive>
<manifest>
<mainClass>${package}.FooBar</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
...
</plugins>
</build>
Since you said that you are using Eclipse, did you know you can export a runnable JAR and all its dependecies via the IDE? Right-click on your project and select Export. Search for "Runnable JAR". You should see this:
Now you have a few options:
Extract required libraries into generated JAR.
This will unpack the third party JARs and repack them, along with your class, into a single JAR.
Package required libraries into generated JAR.
This will include the third party JARs into your JAR, as well as some special Eclipse magic to unpack them when needed.
Copy required libraries into a sub-folder
This will copy the third party JARs into a folder and then update the manifest of your JAR, adding the third-party JAR relative file references to your classpath.
I recently just started toying around with Maven in java. Time comes to test my project, it works fine in the NetBeans window, running the main class found in App.java (com.MyCompany.App), but when I try to run it from a command line I get an error:
java -jar fileName.jar
"No Main Manifest Attribute" in fileName.jar
I have tried adding a manifest.mf file specifying what main is, I've also been into project properties and added it as the main file...
What's going on?
You need the maven-jar-plugin (see Maven's example). This plugin will create the required entries in the manifest file when the project is built.
<project>
...
<build>
<plugins>
...
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.3.2</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>fully.qualified.MainClass</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
...
</plugins>
</build>
...
</project>
You need the version, otherwise, the project won't build. The fully.qualified.MainClass starts at the package hierarchy.
Hope there is a problem in your manifest file. Some basic checks might solve your problem.
it should under /META-INF/MANIFEST.MF
Content should have Main-Class:com.MyCompany.App
If you are using any IDE, there should be an option to export project as runnable jar, you can make use of that to let the IDE take care of correct manifest.
From command line jar cfm filename.jar Manifest.txt com/MyCompany/*.class which generates the Manifest file with following contents
Manifest-Version: 1.0
Created-By: 1.6.0 (Sun Microsystems Inc.)
Main-Class: com.MyCompany.App
And then you can run jar command java -jar fileName.jar.
These type of problems are trivial but kills lot of time, just ensure your contents and location of the file is correct.
You could just use this for command line:
java -cp jarFileName.jar full.package.className
You wouldn't have to go into specifics of the Manifest file in this case.
Setting an Entry Point with the JAR Tool:
The 'e' flag (for 'entrypoint') creates or overrides the manifest's Main-Class attribute. It can be used while creating or updating a JAR file. Use it to specify the application entry point without editing or creating the manifest file.
For example, this command creates app.jar where the Main-Class attribute value in the manifest is set to MyApp:
jar cfe app.jar MyApp MyApp.class
You can directly invoke this application by running the following command:
java -jar app.jar
If the entrypoint class name is in a package it may use a '.' (dot) character as the delimiter. For example, if Main.class is in a package called foo the entry point can be specified in the following ways:
jar cfe Main.jar foo.Main foo/Main.class
If you look at the properties dialog for the project (from project tab, right click on your project and select properties) you'll see that there is a "run" item in the "Categories" window. Click on it and you'll see a dialog where you can specify the Main Class for the jar. That information will end up in your manifest.
I have been having this problem with Netbeans 8.0 and the built-in Maven project for the "Java Application" project prototype. Also I have Maven 3 and I found some of the suggestions on the web don't match the maven code used with Netbeans as well.
Anyway here's a simple recipe for having JAR file to run the main-class and embed dependent libraries. I made this work by comparing other project POM files for projects I found that worked with sub-project JAR-s so if someone with better Maven knowledge spots a gottcha, please speak. Also, I left in some normal stuff to provide context. Example follows:
<properties>
<packageName>trials.example</packageName>
<mainClass>${packageName}.CmdApp</mainClass>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<slf4jVersion>1.7.7</slf4jVersion>
<log4jVersion>1.2.17</log4jVersion>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
This section tells Maven about the project.
packageName ... Is the Java package for the main-class
mainClass ..... The fully qualified name for class with main() method.
You will see these used in the maven-jar-plugin.
The other thing the built-in example prototype didn't do was to package my sub-projects into the JAR so I can run from the command line. This is done with the maven-dependency-plugin below. The interesting bit is in the where we don't need to package the system stuff, and we want the dependant classes wrapped into our JAR.
These are used as follows:
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>2.6</version>
<executions>
<execution>
<id>unpack-dependencies</id>
<phase>package</phase>
<goals>
<goal>unpack-dependencies</goal>
</goals>
<configuration>
<excludeScope>system</excludeScope>
<outputDirectory>${project.build.directory}/classes</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.5</version>
<configuration>
<useDefaultManifestFile>true</useDefaultManifestFile>
<archive>
<manifest>
<mainClass>${mainClass}</mainClass>
<packageName>${packageName}</packageName>
<addClasspath>true</addClasspath>
<classpathPrefix>classes/</classpathPrefix>
</manifest>
<manifestEntries>
<mode>development</mode>
<url>${pom.url}</url>
</manifestEntries>
</archive>
</configuration>
</plugin>
</plugins>
</build>
Hope that saves you the few hours of checking and testing to make it happen. Cheers, Will.