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Maven build no main manifest attribute

I'm building a small app with Maven that has dependencies and is an executable jar file.
Here is my 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>com.company</groupId>
<artifactId>site-downloader</artifactId>
<version>1.0.0</version>
<packaging>jar</packaging>
<properties>
<maven.compiler.target>1.8</maven.compiler.target>
<maven.compiler.source>1.8</maven.compiler.source>
</properties>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.seleniumhq.selenium/selenium-java -->
<dependency>
<groupId>org.seleniumhq.selenium</groupId>
<artifactId>selenium-java</artifactId>
<version>3.141.59</version>
</dependency>
<!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.6</version>
</dependency>
<dependency>
<groupId>com.company.siteripper</groupId>
<artifactId>common-interfaces</artifactId>
<version>1.0.0</version>
</dependency>
</dependencies>
<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>
</project>
The build completes with no issues but when executing the jar it writes
no main manifest attribute, in local maven repo / my jar.
I sought aid at the docs and Baeldung too to no avail.
I seek assistance to make the jar include its dependencies and is executable at the same time.
Edit:
I updated my pom to use the jar and the dependencies plugins instead of the assembly. Here is the updated pom:
<?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>com.company</groupId>
<artifactId>site-downloader</artifactId>
<version>1.0.0</version>
<packaging>jar</packaging>
<properties>
<maven.compiler.target>1.8</maven.compiler.target>
<maven.compiler.source>1.8</maven.compiler.source>
</properties>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.seleniumhq.selenium/selenium-java -->
<dependency>
<groupId>org.seleniumhq.selenium</groupId>
<artifactId>selenium-java</artifactId>
<version>3.141.59</version>
</dependency>
<!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.6</version>
</dependency>
<dependency>
<groupId>com.company.siteripper</groupId>
<artifactId>common-interfaces</artifactId>
<version>1.0.0</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>
com.company.Main
</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>prepare-package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>
${project.build.directory}/libs
</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
But I get a NoClassDefFoundError when running it:
C:\Users\myusername\Documents\Commands>call java -jar
D:.m2\repository\com\company\site-downloader\1.0.0\site-downloader-1.0.0.jar
-9gag https://9gag.com/gag/arGEvRX?ref C:\Users\myusername\Documents\sites\data\android Error: A JNI error
has occurred, please check your installation and try again Exception
in thread "main" java.lang.NoClassDefFoundError:
org/openqa/selenium/WebDriver
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Unknown Source)
at java.lang.Class.privateGetMethodRecursive(Unknown Source)
at java.lang.Class.getMethod0(Unknown Source)
at java.lang.Class.getMethod(Unknown Source)
at sun.launcher.LauncherHelper.validateMainClass(Unknown Source)
at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source) Caused by: java.lang.ClassNotFoundException:
org.openqa.selenium.WebDriver
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 7 more

To create an executable jar, you have to use the following maven jar plugin. I provide below the code snippet.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>
your main class
</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
For more details, refer below the github link to get an idea of how to create executable/runnable jar.
https://github.com/debjava/runnableJar
As per docs, Maven Assembly Plugin for Maven is primarily intended to
allow users to aggregate the project output along with its
dependencies, modules, site documentation, and other files into a
single distributable archive.
Refer below the details of Maven Assembly plugin.
http://maven.apache.org/plugins/maven-assembly-plugin/

This is how I solved your issue:
Please ignore business logic,
since I am using MongoDB, added MongoDB driver as a dependency and able to run with java -jar command.
The end goal is same as of yours.
I am using maven-shade plug-in.
Checkout project from Github source code:
unzip, build, test
OR
1. Created a maven project
mvn archetype:generate -DarchetypeGroupId=org.apache.maven.archetypes -DarchetypeArtifactId=maven-archetype-quickstart -DarchetypeVersion=1.4
Update pom.xml with following, added mongo client code from OP and printing collection names
Execute
mvn clean package
Execute
java -jar test.jar
output I got is:
INFO: Opened connection [connectionId{localValue:1, serverValue:9}] to localhost:27017
Jun 01, 2019 8:17:22 PM com.mongodb.diagnostics.logging.JULLogger log
INFO: Monitor thread successfully connected to server with description ServerDescription{address=localhost:27017, type=STANDALONE, state=CONNECTED, ok=true, version=ServerVersion{versionList=[4, 0, 5]}, minWireVersion=0, maxWireVersion=7, maxDocumentSize=16777216, logicalSessionTimeoutMinutes=30, roundTripTimeNanos=2249770}
Jun 01, 2019 8:17:22 PM com.mongodb.diagnostics.logging.JULLogger log
INFO: Opened connection [connectionId{localValue:2, serverValue:10}] to localhost:27017
admin
config
local
test
[XenonSuite] Successfully connected to MongoDB
pom.xml(ignore package names)
Check shade plugin configuration
<?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>test</groupId>
<artifactId>test</artifactId>
<version>1.0-SNAPSHOT</version>
<name>test</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<mainClass>test.App</mainClass>
</properties>
<packaging>jar</packaging>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.mongodb/mongo-java-driver -->
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongo-java-driver</artifactId>
<version>3.10.2</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.1.1</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>3.1.1</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.1.1</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.2.1</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<shadedArtifactAttached>true</shadedArtifactAttached>
<transformers>
<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>test.App</mainClass>
</transformer>
</transformers>
<finalName>test</finalName>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
There are multiple ways to solve this problem
Ref: https://www.baeldung.com/executable-jar-with-maven

Springboot application.properites not read

I've developed a springboot application with Maven in Eclipse. The class annotated with #SpringBootApplication reads the application.properties inside src/main/resources. Inside Eclipse everything works fine.
Using Maven I've generated a fat jar, this is the plugin I'm using:
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
<configuration>
<classifier>exec</classifier>
</configuration>
</execution>
</executions>
</plugin>
In the target folder 2 jars are generated, one named fatjar-exec.jar and the other fatjar.jar. When I run the command java -jar fatjar-exec.jar an exception is thrown since the application is not able to read the application.properties file.
I have also unzipped the jar and correctly the applciation.properties is located under BOOT-INF/classes folder. Any hints?

Please compare the contents of generated fatjars.
The regular one (without exec) has only one copy of springboot classes,
while the one generated with the clasifier has two.
one under /org/springframework/boot/loader (expected)
second under /BOOT-INF/classes/org/springframework/boot/loader
Probably the order of classpath search causes the file from the unexpected location to be picked up, and it cannot find the properties in /BOOT-INF/classes
IMHO the simplest version works best:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
Check Custom repackage classifier for details how to configure maven if you want to keep the origial file (you were missing <id>repackage</id>).

This is working for me fine too.
My POM.xml is as follows :
<?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>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.3.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<groupId>xxx</groupId>
<artifactId>yyy</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</name>
<packaging>jar</packaging>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
<configuration>
<classifier>exec</classifier>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
mvn package -DskipTests
java -jar xxx-0.0.1-SNAPSHOT.jar

No classDefinitionFound error Spring Boot

I'm getting the following error when trying to run my jar file on the command line:
$ java -jar target/Controller-0.0.1-SNAPSHOT.jar
Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication
at com.vismark.Controller.App.main(App.java:11)
Caused by: java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 1 more
The project runs just fine on eclipse, but this error shows up when running it via commandline.
Below is my pom file:
<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>com.vismark</groupId>
<artifactId>Controller</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>Controller</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>2.0.4.RELEASE</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.4</version>
<configuration>
<archive>
<manifest>
<mainClass>com.vismark.Controller.App</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
</plugins>
</build>
</project>
I'm likely missing something in my pom, I;m just not sure what it is. Where did I go wrong?

You most likely want to package an executable JAR. Since you are using Spring Boot you should follow chapter 71. Spring Boot Maven Plugin which explains how to do it using Spring Boot Maven Plugin.
Normally this is done by adding following build configuration to your pom.xml which be trigger during package phase.
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>2.0.4.RELEASE</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
As a note you are using ancient JUnit 3.8.1, you really should upgrade.

ClassNotFoundException on a Maven Project using Selenium [duplicate]

This question already has answers here:
NoClassDefFoundError on Maven dependency
(7 answers)
Closed 5 years ago.
I wrote a small Maven Project in Netbeans using the Selenium HtmlUnitDriver.
The Project works when i'm starting it from the IDE. But when i'm using the command java -jar to open the jar file it reports an Error.
Exception in thread "main" java.lang.NoClassDefFoundError: org/openqa/selenium/htmlunit/HtmlUnitDriver
at com.mycompany.myPackage.classNameUI.<init>(classNameUI.java:26)
at com.mycompany.myPackage.mainClass.main(mainClass.java:20)
Caused by: java.lang.ClassNotFoundException: org.openqa.selenium.htmlunit.HtmlUnitDriver
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 2 more
the manifest.mf got the right Mainclass: path
Versions:
Netbeans 8.2
Maven 4.0.0
Selenium 2.53.1
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>com.mycompany</groupId>
<artifactId>MyProject</artifactId>
<version>User</version>
<packaging>jar</packaging>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.seleniumhq.selenium</groupId>
<artifactId>selenium-java</artifactId>
<version>2.53.1</version>
</dependency>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.2</version>
</dependency>
<dependency>
<groupId>net.sourceforge.htmlunit</groupId>
<artifactId>htmlunit</artifactId>
<version>2.25</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.4</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>com.mycompany.mypackage.mainClass</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
</plugins>
</build>

I think it might be because you don't include in your classpath the dependencies your program is using, to solve this:
Add to the "maven-jar-plugin" under <addClasspath>:
<classpathPrefix>lib/</classpathPrefix>
Then add this plugin to the build section in your pom.xml:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>prepare-package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/lib</outputDirectory>
<overWriteReleases>false</overWriteReleases>
<overWriteSnapshots>false</overWriteSnapshots>
<overWriteIfNewer>true</overWriteIfNewer>
</configuration>
</execution>
</executions>
</plugin>
See the doc for more details: https://maven.apache.org/plugins/maven-dependency-plugin/usage.html

Spring boot maven plugin with a main class in a dependency

I have a perhaps unusual case where I want to use the spring-boot maven plugin to perform 'mvn spring:start' (before integration tests) on a project with spring services, but the class with the main method is in a jar file. The reason for this is that there will be a number of these spring services that require some common structures in place when started up for testing purposes, so the idea is that there will be a common jar with the common stuff and the class with the main method and each individual service project will simply reuse that.
Unfortunately I am getting ClassNotFoundException for the class with the main method - spring boot clearly isn't looking in the jar files but only in the compiled classes of this project.
The pom in question (trimmed):
<?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>com.something</groupId>
<artifactId>something</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencies>
...
<dependency>
<groupId>com.something</groupId>
<artifactId>artifact-with-main-method</artifactId>
<version>0.0.1-SNAPSHOT</version
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>1.4.2.RELEASE</version>
<dependencies>
<dependency>
<groupId>com.something</groupId>
<artifactId>artifact-with-main-method</artifactId>
<version>0.0.1-SNAPSHOT</version
</dependency>
</dependencies>
<configuration>
<mainClass>com.something.Application</mainClass>
<requiresUnpack>
<dependency>
<groupId>com.something</groupId>
<artifactId>artifact-with-main-method</artifactId>
</dependency>
</requiresUnpack>
</configuration>
<executions>
<execution>
<id>pre-integration-test</id>
<goals>
<goal>start</goal>
</goals>
</execution>
<execution>
<id>post-integration-test</id>
<goals>
<goal>stop</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
Output:
java.lang.ClassNotFoundException: com.something.Application
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at org.springframework.boot.maven.AbstractRunMojo$LaunchRunner.run(AbstractRunMojo.java:501)
at java.lang.Thread.run(Thread.java:745)
UPDATE:
I gave up trying to get this to work. I ended up using the mvn:exec plugin to execute a java command doing what I needed it instead. It works well enough.

Do you have:
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
in the dependency too? If yes, then it will make the dependency module impossible to import to the current module/project. So, remove it from the dependency, and add it to the current module that you are importing the main class into.