How to set classpath for a maven project

Question

I created a maven project with eclipse and made jar file from it with this below comand

mvn package

when i try to know my mvn project config is true or not with this command

mvn exec:java -D exec.mainClass="giraph.helloworld.App"

i get this error :

failed to execute goal
org.codehaus.mojo:exec-maven-plugin:1.2.1:java(default-cli) on project helloworld: An exception occured while executing the java class. null: InvocationTargetException: No arguments were provided

POM.xml setting of project is as follows. I will be so grateful if anyone can help me and specifies the reasons of this error?

  <project xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
  http://maven.apache.org/xsd/maven-4.0.0.xsd">  
  <modelVersion>4.0.0</modelVersion>

    <groupId>giraph</groupId>   
    <artifactId>helloworld</artifactId>  
    <version>0.0.1-SNAPSHOT</version>   
    <packaging>jar</packaging>

    <name>helloworld</name>   
    <url>http://maven.apache.org</url>

    <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>            
     </properties>

    <dependencies>      
    <dependency>
        <groupId>org.apache.giraph</groupId>
        <artifactId>giraph-core</artifactId>
        <version>1.1.0</version>    
    </dependency>       
    <dependency>    
        <groupId>org.apache.maven.plugins</groupId>  
        <artifactId>maven-compiler-plugin</artifactId>  
        <version>2.0.2</version>    
    </dependency>       
   <dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-core</artifactId>
        <version>1.2.1</version>
   </dependency>    
   <dependency>     
    <groupId>org.apache.maven.plugins</groupId>  
    <artifactId>maven-surefire-plugin</artifactId>  
    <version>2.10</version>
   </dependency>  
 </dependencies>
 <build> 
   <plugins>
     <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.2.1</version>
        <executions>
        <execution>
          <goals>
            <goal>java</goal>
          </goals>
         <configuration>
           <mainClass>giraph.helloworld.App</mainClass>
         </configuration>
        </execution>
       </executions>
     </plugin>
  </plugins>
 </build> 
</project>

I add mainClass in POM file using exec-maven-plugin. I think POM file acts like a manifest . is it true? — Erfan Farhangy, Feb 13 '17 at 01:46
POM is supposed to generate that but there are some things missing in your POM. Check this out - https://www.mkyong.com/maven/how-to-create-a-manifest-file-with-maven/ — opensam, Feb 13 '17 at 01:47
I dont see manifest file in my POM file. is it exist in my project? — Erfan Farhangy, Feb 13 '17 at 01:52
If you are using maven on eclipse, the manifest file must be somewhere inside target folder — opensam, Feb 13 '17 at 01:56
I think manifest file add into final jar file. one another question? is require to specify all of the dependencies to final executable jar file? — Erfan Farhangy, Feb 13 '17 at 01:57
I am assuming you are referring to packaging all your dependencies (libraries) into your application jar. The answer is, yes you can. You can modify your POM file and add some plugins to create something called 'uber' jar. Maybe you can look into that. — opensam, Feb 13 '17 at 02:02
i cant find manifest file inside target folder. may be mvn package command cant executes completely. — Erfan Farhangy, Feb 13 '17 at 02:02
yes i checked it. i mounted jar file file and saw that manifest file is added into jar file. and has below texts. — Erfan Farhangy, Feb 13 '17 at 02:07
Manifest-version: 1.0 Archive-version: plexus archiver created by: Apache maven Built by : erfan build-jdk: 1.8.0_121 — Erfan Farhangy, Feb 13 '17 at 02:09

score 1 · Accepted Answer · edited May 23 '17 at 11:53

1

I think the problem is that your manifest file does not contain information about the entry point (the main class) of your jar. See Setting an Application entry point.

There are many ways to rectify this problem. You can use maven assembly plugin. For more details, check here

edited May 23 '17 at 11:53

Community

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answered Feb 13 '17 at 02:16

opensam

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How to set classpath for a maven project

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