Develop Reference

maven-compiler-plugin not found

I am learning Selenium and I would like to try add the maven-compiler-plugin to pom.xml and reimport maven settings. So I found this example to do it http://maven.apache.org/plugins/maven-compiler-plugin/examples/set-compiler-source-and-target.html and tried to add the code to the pom.xml. But the vrsion from the example 3.8.1 is red like on the screenshot. What it means? It is a copy from example.
Here is the whole pom.xml
<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>camaj.vladimir</groupId>
<artifactId>selenium-maven</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.seleniumhq.selenium</groupId>
<artifactId>selenium-java</artifactId>
<version>3.141.59</version>
</dependency>
<dependency>
<groupId>org.seleniumhq.selenium</groupId>
<artifactId>selenium-server</artifactId>
<version>3.141.59</version>
</dependency>
<dependency>
<groupId>org.seleniumhq.selenium</groupId>
<artifactId>selenium-chrome-driver</artifactId>
<version>3.141.59</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>4.1.1</version>
</dependency>
<dependency>
<groupId>com.google.code.tempus-fugit</groupId>
<artifactId>tempus-fugit</artifactId>
<version>1.1</version>
</dependency>
<dependency>
<groupId>com.codeborne</groupId>
<artifactId>phantomjsdriver</artifactId>
<version>1.4.4</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
</project>

In my case, I have changed the tags from plugin to dependency like it is in the Maven Repository.
<dependency>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
</dependency>

In my case the groupId for the plugin was missing:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
...

In my case, Spring Boot code works fine without changing anything, however, it gives the same error when I tried to commit in Git.
To solve this, I add the version info as follows and it worked.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler-plugin.version}</version>
...

I've faced this issue with my old project (which was 100% working on my old ItelliJ IDEA) and newly installed ItelliJ IDEA:
in the pom.xml I had this:
<build>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.2</version>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
</plugins>
</build>
And IDEA throwed an error maven-compiler-plugin not found. I've added
<groupId>org.apache.maven.plugins</groupId>
and IDEA found the plugin, and after that I was free to remove org.apache.maven.plugins without breaking IDEA

I got this error with IntelliJ. tried many ways, the below worked for me:
Close your IDE.
Delete "*.iml" and ".idea" -directories(present in the root folder of project)
Run "mvn clean install" from the command-line
Re-import your project into IDEA

In IntelliJ you can right click on 3.8.1 scroll down to Maven and select "Reimport". This solved the issue for me.

In my case, invalidating cache and restarting solved the issue.

Add the Following code in your pom the issue will resolve
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.0</version>
<configuration>
<source>8</source>
<target>8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>3.0.0-M1</version>
<configuration>
<useSystemClassLoader>false</useSystemClassLoader>
<forkCount>1</forkCount>
<useFile>false</useFile>
<skipTests>false</skipTests>
<testFailureIgnore>true</testFailureIgnore>
<forkMode>once</forkMode>
<suiteXmlFiles>
<suiteXmlFile>testing.xml</suiteXmlFile>
</suiteXmlFiles>
</configuration>
</plugin>
</plugins>
</build>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
Make sure you are reimporting your dependency after adding plugins

I went to
.m2\repository\org\apache\maven\plugins\maven-compiler-plugin
and removed older version. It worked

You need to update your project so that the dependencies are updated from Maven side.
To update:
Change the file structure to project view.
Right click on project name -> Maven -> Reload project
And it will download all the necessary dependencies.

One reason could be due to proxy setup on your system in Maven settings.
You can remove/backup the previous maven settings.xml file and this should work.
mv ~/.m2/settings.xml ~/.m2/settings.xml.bak

Running maven project in cmd

I'm have to run maven project in cmd. This is my pom.xml file:
http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
<groupId>com.mycompany.app</groupId>
<artifactId>my-app</artifactId>
<version>1.0-SNAPSHOT</version>
<name>my-app</name>
<!-- FIXME change it to the project's website -->
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.7</maven.compiler.source>
<maven.compiler.target>1.7</maven.compiler.target>
<maven.compiler.release>11</maven.compiler.release>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.16</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.4.2.Final</version>
</dependency>
</dependencies>
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
</plugin>
</plugins>
</pluginManagement>
</build>
The project is running perfectly fine in IDE (Eclipse), but when I try to run it run it from command line I get the following error:
Exception in thread "main" java.lang.NoClassDefFoundError: org/hibernate/cfg/Configuration
at com.mycompany.app.App.main(App.java:15)
Caused by: java.lang.ClassNotFoundException: org.hibernate.cfg.Configuration
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:583)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
... 1 more

The problem in your case is that you dont have the dependencies in the classpath. You can use a maven pluging to obtain such.
<build>
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<configuration>
<archive>
<manifest>
<mainClass>fully.qualified.MainClass</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id> <!-- this is used for inheritance merges -->
<phase>package</phase> <!-- bind to the packaging phase -->
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
Source How can I create an executable JAR with dependencies using Maven?

It really depends on how you setup your project, but what your stack trace is saying literally that JVM could not locate mentioned class. Now, you can imagine (this is just only one of many possible issues) - you have your code referencing 'Configuration' class somewhere, but when the project runs from a command line - JVM can not find it.
I would recommend taking a look at this topic to understand received error. Many thoughts were given and it was explained well.
Essentially once you get all your dependencies in place, that error will goaway and if you're using TestNG or JUnit, you won't need a main class. You will run your tests with just mvn clean test Or even shorter mvn if you add <defaultGoal>clean test</defaultGoal> to POM.

unable to find logger class while running a maven build jar file

I am trying to write a maven integrated Java API. I have included log4j for logging purpose. Which works well when running through eclipse, but when maven package is done and the jar is run it is unable to run from cmd line using java -jar jar_name.jar throwing an error
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Logger
Now the log4j.properties file is placed under src/main/resources folder. And the pom.xml is mentioned. Have tried searching for answers but none worked for me.
Any help available
<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>Weather_Simulator</groupId>
<artifactId>weather_simulator</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>weather_simulator</name>
<url>http://maven.apache.org</url>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>com.test.weather.simulator.MainClass</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<!-- NOTE: We don't need a groupId specification because the group is
org.apache.maven.plugins ...which is assumed by default.
-->
<artifactId>maven-assembly-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
</plugins>
</build>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.1</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-configuration2</artifactId>
<version>2.1.1</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>2.6.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>

Your <scope> in your pom.xml appears to be wrong. Try this (notice I've changed "test" to "compile").
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>2.6.1</version>
<scope>compile</scope> <!-- look here -->
</dependency>
The way you currently have your pom.xml configured (with "test"), maven will only provide the log4j jar when doing "mvn test". If you need the jar at both compile time and run time (which is the scenario that appears to be causing problems for you), the scope needs to be "compile".
Note that "compile" is the default scope, so if you leave the <scope> element off, the scope will be "compile".
From the maven docs: "This [compile] is the default scope, used if none is specified. Compile dependencies are available in all classpaths of a project. Furthermore, those dependencies are propagated to dependent projects"
For more info about maven "scopes" look here.

This is a classpath problem, the jar generated by Maven contains only your classes. To fix this you can pack all the dependencies inside your project jar: How can I create an executable JAR with dependencies using Maven?

There are two things you should be aware if you like to create an executable jar which contains all dependent jars you have to use maven-assembly-plugin as you already did but you forgot to bind it to the life cycle...which looks like this:
<project>
[...]
<build>
[...]
<plugins>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id> <!-- this is used for inheritance merges -->
<phase>package</phase> <!-- bind to the packaging phase -->
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
[...]
</project>
Furthermore having plugins as dependencies is simply wrong..
<dependency>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.1</version>
</dependency>
This means remove this entry from your pom file.
Defining a dependency with a scope test means it will be available only during the unit tests which means also it will never being packaged into a resulting jar file. This means you have to change the following:
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>2.6.1</version>
<scope>test</scope>
</dependency>
into the following:
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>2.6.1</version>
</dependency>
After you have fixed those issues you should be able to build your app via:
mvn clean package
and find the resulting jar file which contains the dependencies in the target directory named like weather_simulator-1.0.0-SNAPSHOT-jar-with-dependencies.jar which you should use to call your app.

Not adding JARs to staging folder on Google Cloud when using Maven

I'm running integration tests on the cloud for the Google Cloud Dataflows that I have written; checking that they read from Pub/Sub and write to BigQuery correctly, but when using Maven (mvn clean install), the staging folder is not populated with the required JARs. The only JAR that appears is a surefirebooter.jar. As a result, I get a NoClassDefFoundError for PipelineOptions (most likely because it is the first class from a dependency that's trying to be referenced) in the Stackdriver logs, and consequently the tests fail. Since they're running on the cloud I am indeed using a DataflowRunner as opposed to a DirectRunner.
When I run the integration tests from my IDE they work fine; the staging folder is populated with all the JARs and all is well. Also, when I run the tests using Maven but with a DirectRunner the tests run successfully, thus my problem only occurs when using Maven and a DataflowRunner. I assume that problem therefore lies with the pom.xml file, which I have given below:
<?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>group</groupId>
<artifactId>artifact</artifactId>
<version>1.0-SNAPSHOT</version>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.5</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<appendAssemblyId>false</appendAssemblyId>
<archive>
<manifest>
<addClasspath>true</addClasspath>
</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>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>com.google.cloud.dataflow</groupId>
<artifactId>google-cloud-dataflow-java-sdk-all</artifactId>
<version>2.0.0-beta3</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.25</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.7.25</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<version>5.0.0-M3</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.mockito</groupId>
<artifactId>mockito-all</artifactId>
<version>2.0.2-beta</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
Anyone know why this is happening and how I may resolve it?

When staging files, the Dataflow runner will automatically stage the the classes available to the current class loader. I believe that surefire plays some tricks with the classloader to make the tests easier to run.
One option would be to specify filesToStage on the pipeline options, which will override the normal "detect JARs to stage from the class loader". Alternatively, look at how surefire is managing the classpath, and make sure the SDK JARs are available in the classloader the test is running in.

How to build project like Eclipse Clean on Maven pom.xml

I need help on running maven project. I can run the project on Eclipse, and I tried to deploy / run it on Jenkins CI but without success.
I made a maven project with custom folder structure (not following the default).
Below is the structure:
I can run the project successfully through Eclipse by cleaning the project first where I believe Eclipse build all java files for me. Below is the 'target' folder looks like after I clean the project through Eclipse (not maven clean)
However, when I delete the content of 'target' folder, and run maven -clean and maven -install I received an error like this:
I believe it's because I did not set anything on the pom.xml about building all java classes. However I do not know how to do it ? Can you help me? Changing structure is avoided right now. Thanks
Below is the pom.xml
<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>bukalapak</groupId>
<artifactId>bukalapak</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.seleniumhq.selenium</groupId>
<artifactId>selenium-java</artifactId>
<version>2.46.0</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.seleniumhq.selenium</groupId>
<artifactId>selenium-remote-driver</artifactId>
<version>2.46.0</version>
</dependency>
<dependency>
<groupId>org.testng</groupId>
<artifactId>testng</artifactId>
<version>6.9.4</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<!-- <resources>
<resource>
<directory>src/bukalapak</directory>
</resource>
</resources> -->
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.14.1</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
</manifest>
</archive>
<forkMode>never</forkMode>
<suiteXmlFiles>
<suiteXmlFile>testsuite/TestSuiteBukalapak.xml</suiteXmlFile>
</suiteXmlFiles>
</configuration>
</plugin>
</plugins>
</build>
</project>

You can use maven-compiler-plugin. Example:
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.3</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
</plugins>
</build>

If you don't use the default directory structure, you have to configure the source directory appropriately. In your case, the correct configuration would be:
<build>
<sourceDirectory>src</sourceDirectory>
</build>
Otherwise Maven would look in the default folder structure.