ClassNotFoundExeption when running with mvn exec:java [duplicate] - maven

Question

This question already has answers here:
Maven: lifecycle phase to run a program?
(2 answers)
Closed 2 years ago.
Looking to run a basic console app with maven:
nicholas#mordor:~/NetBeansProjects/mavenchimp$
nicholas#mordor:~/NetBeansProjects/mavenchimp$ mvn clean exec:java
[INFO] Scanning for projects...
[INFO]
[INFO] -----------------< tech.saundersconsulting:mavenchimp >-----------------
[INFO] Building mavenchimp 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) # mavenchimp ---
[INFO]
[INFO] --- exec-maven-plugin:3.0.0:java (default-cli) # mavenchimp ---
[WARNING]
java.lang.ClassNotFoundException: tech.mavenchimp.App
at java.net.URLClassLoader.findClass (URLClassLoader.java:471)
at java.lang.ClassLoader.loadClass (ClassLoader.java:589)
at java.lang.ClassLoader.loadClass (ClassLoader.java:522)
at org.codehaus.mojo.exec.ExecJavaMojo$1.run (ExecJavaMojo.java:246)
at java.lang.Thread.run (Thread.java:834)
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.465 s
[INFO] Finished at: 2020-12-06T08:06:26-08:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:3.0.0:java (default-cli) on project mavenchimp: An exception occured while executing the Java class. tech.mavenchimp.App -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
directory tree
nicholas#mordor:~/NetBeansProjects/mavenchimp$ tree
.
├── pom.xml
└── src
├── main
│   └── java
│   └── tech
│   └── mavenchimp
│   ├── App.java
│   └── Chimp.java
└── test
└── java
7 directories, 3 files
the pom
nicholas#mordor:~/NetBeansProjects/mavenchimp$ cat pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<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>tech.saundersconsulting</groupId>
<artifactId>mavenchimp</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
<exec.mainClass>tech.mavenchimp.App</exec.mainClass>
</properties>
</project>
the code
nicholas#mordor:~/NetBeansProjects/mavenchimp$ cat src/main/java/tech/mavenchimp/App.java
package tech.mavenchimp;
import java.util.logging.Logger;
public class App {
private static final Logger log = Logger.getLogger(App.class.getName());
private void runApp() {
log.info("running..");
Chimp chimp = new Chimp();
chimp.connect();
}
public static void main(String[] args) {
new App().runApp();
}
}
nicholas#mordor:~/NetBeansProjects/mavenchimp$
where the pom.xml was generated by Netbeans and I simply added the line:
<exec.mainClass>tech.mavenchimp.App</exec.mainClass>
in order to be able to run the exec command with maven.
Running maven with the -e swith gives:
Caused by: java.lang.ClassNotFoundException: tech.mavenchimp.App
how is that class specified beyond the setting in the pom.xml as above?

Answer 1

Solution:
nicholas#mordor:~/NetBeansProjects/mavenchimp$
nicholas#mordor:~/NetBeansProjects/mavenchimp$ mvn clean compile exec:java
[INFO] Scanning for projects...
[INFO]
[INFO] -----------------< tech.saundersconsulting:mavenchimp >-----------------
[INFO] Building mavenchimp 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) # mavenchimp ---
[INFO] Deleting /home/nicholas/NetBeansProjects/mavenchimp/target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) # mavenchimp ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /home/nicholas/NetBeansProjects/mavenchimp/src/main/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) # mavenchimp ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 2 source files to /home/nicholas/NetBeansProjects/mavenchimp/target/classes
[INFO]
[INFO] --- exec-maven-plugin:3.0.0:java (default-cli) # mavenchimp ---
Dec 06, 2020 8:17:54 AM tech.mavenchimp.App runApp
INFO: running..
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4.739 s
[INFO] Finished at: 2020-12-06T08:17:54-08:00
[INFO] ------------------------------------------------------------------------
nicholas#mordor:~/NetBeansProjects/mavenchimp$
Wouldn't exec depend on compile?