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Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile)

I want to generate a JAR but every time I get this error:
Console log
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.160 s
[INFO] Finished at: 2021-11-27T00:37:06+01:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile)
on project qengine: Fatal error compiling: invalid target release: 9 -> [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/MojoExecutionExceptions
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>napd</groupId>
<artifactId>qengine</artifactId>
<version>0.0.1-SNAPSHOT</version>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.eclipse.rdf4j</groupId>
<artifactId>rdf4j-bom</artifactId>
<version>3.7.3</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.eclipse.rdf4j</groupId>
<artifactId>rdf4j-client</artifactId>
<type>pom</type>
</dependency>
<dependency>
<groupId>org.apache.jena</groupId>
<artifactId>apache-jena</artifactId>
<type>pom</type>
<version>3.9.0</version>
</dependency>
</dependencies>
<build>
<plugins>
<!-- <plugin> <artifactId>maven-compiler-plugin</artifactId> <version>3.8.1</version>
<configuration> <source>8</source> <target>8</target> </configuration> </plugin>
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jar-plugin</artifactId>
<configuration> <archive> <manifest> <mainClass>qengine.Main</mainClass>
</manifest> </archive> </configuration> </plugin> -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>3.2.0</version>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/allJars</outputDirectory>
<overWriteReleases>false</overWriteReleases>
<overWriteSnapshots>false</overWriteSnapshots>
<overWriteIfNewer>true</overWriteIfNewer>
</configuration>
</execution>
</executions>
</plugin>
<!-- <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId>
<configuration> <source>9</source> <target>9</target> </configuration> </plugin> -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>9</source>
<target>9</target>
</configuration>
</plugin>
</plugins>
</build>
</project>

(1) Is the JAVA_HOME variable configured to the JDK 9 path?
(2) Try replacing the configuration for maven-compiler-plugin:
<configuration>
<fork>true</fork>
<executable>javac9</executable>
</configuration>

Deploy Java Spring Boot Jar to Maven central

I have developped a jar library used in multi-module Java Spring Boot projects but I want now I would like to upload it to Maven central repository.
To do that I created a new project containing only my library that I adapted to make it buildable and then published it into a Github repository.
I have then followed this post to deploy it How to publish JAR to Maven central to Maven but didn't succeed as I have a 401 Forbidden error when using mvn clean deploy.
Here is the full error thrown by IntelliJ :
[ERROR] Failed to execute goal org.sonatype.plugins:nexus-staging-maven-plugin:1.6.7:deploy (injected-nexus-deploy) on project okta-connector: Failed to deploy artifacts: Could not transfer artifact io.github.lyvoc:okta-connector:jar.asc:javadoc:1.0-20210427.100037-1 from/to ossrh (https://oss.sonatype.org/cont
ent/repositories/snapshots): Transfer failed for https://oss.sonatype.org/content/repositories/snapshots/io/github/my_user/project-connector/1.0-SNAPSHOT/project-connector-1.0-20210427.100037-1-javadoc.jar.asc 401 Unauthorized -> [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
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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.sonatype.oss</groupId>
<artifactId>oss-parent</artifactId>
<version>9</version>
</parent>
<groupId>io.github.my_user</groupId>
<artifactId>project-connector</artifactId>
<version>1.0-SNAPSHOT</version>
<name>project-connector</name>
<description>Project API connector</description>
<packaging>jar</packaging>
<properties>
<java.version>1.8</java.version>
<spring-boot-starter-version>2.4.4</spring-boot-starter-version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>${spring-boot-starter-version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<version>${spring-boot-starter-version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
<scope>compile</scope>
</dependency>
</dependencies>
<distributionManagement>
<snapshotRepository>
<id>ossrh</id>
<url>https://oss.sonatype.org/content/repositories/snapshots</url>
</snapshotRepository>
<repository>
<id>ossrh</id>
<url>https://oss.sonatype.org/service/local/staging/deploy/maven2/</url>
</repository>
</distributionManagement>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-source-plugin</artifactId>
<version>2.2.1</version>
<executions>
<execution>
<id>attach-sources</id>
<goals>
<goal>jar-no-fork</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-javadoc-plugin</artifactId>
<version>2.9.1</version>
<executions>
<execution>
<id>attach-javadocs</id>
<goals>
<goal>jar</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-gpg-plugin</artifactId>
<version>1.5</version>
<executions>
<execution>
<id>sign-artifacts</id>
<phase>verify</phase>
<goals>
<goal>sign</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.sonatype.plugins</groupId>
<artifactId>nexus-staging-maven-plugin</artifactId>
<version>1.6.7</version>
<extensions>true</extensions>
<configuration>
<serverId>ossrh</serverId>
<nexusUrl>https://oss.sonatype.org/</nexusUrl>
<autoReleaseAfterClose>true</autoReleaseAfterClose>
</configuration>
</plugin>
</plugins>
</build>
</project>
My .m2/settings.xml :
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 https://maven.apache.org/xsd/settings-1.0.0.xsd">
<localRepository>${user.home}/.m2/repository</localRepository>
<interactiveMode>true</interactiveMode>
<offline>false</offline>
<servers>
<server>
<id>ossrh</id>
<username>sonatype_username</username>
<password>my_password</password>
</server>
</servers>
<profiles>
<profile>
<id>ossrh</id>
<activation>
<activeByDefault>true</activeByDefault>
</activation>
<properties>
<gpg.executable>gpg</gpg.executable>
<gpg.passphrase>my_password</gpg.passphrase>
</properties>
</profile>
</profiles>
</settings>
I used gpg and not gpg2 for the public key as I had this one installed.
I can't find where the issue comes from as the similar cases I have found are simply using the wrong password or forgot to put -SNAPSHOT for artifact version.
Thank you for any help !

Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:3.2.0:jar (attach-javadocs)

I am trying to install CGView for which the jar file is build using maven.
The command is:
mvn package
But it gives me the following error
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4:58.749s
[INFO] Finished at: Tue Feb 23 16:07:13 IST 2021
[INFO] Final Memory: 28M/557M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:3.2.0:jar (attach-javadocs) on project cgview: Unable to parse configuration of mojo org.apache.maven.plugins:maven-javadoc-plugin:3.2.0:jar for parameter additionalOptions: Cannot assign configuration entry 'additionalOptions' with value '-Xdoclint:none' of type java.lang.String to property of type java.lang.String[] -> [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/PluginConfigurationException
I have tried deleting .m2/repository using :
rm -rf ~/.m2/repository
But still it gives me the same error. I think it has to do something with java environment. Please guide.
Here is my pom.xml 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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>ca.ualberta.stothard.cgview</groupId>
<artifactId>cgview</artifactId>
<packaging>jar</packaging>
<version>2.0.2-SNAPSHOT</version>
<name>cgview</name>
<url>http://maven.apache.org</url>
<properties>
<maven.compiler.source>1.7</maven.compiler.source>
<maven.compiler.target>1.7</maven.compiler.target>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
</properties>
<dependencies>
<dependency>
<groupId>org.apache.xmlgraphics</groupId>
<artifactId>batik-awt-util</artifactId>
<version>1.13</version>
</dependency>
<dependency>
<groupId>org.apache.xmlgraphics</groupId>
<artifactId>batik-dom</artifactId>
<version>1.13</version>
</dependency>
<dependency>
<groupId>org.apache.xmlgraphics</groupId>
<artifactId>batik-svggen</artifactId>
<version>1.13</version>
</dependency>
<dependency>
<groupId>org.apache.xmlgraphics</groupId>
<artifactId>batik-util</artifactId>
<version>1.13</version>
</dependency>
<dependency>
<groupId>org.apache.xmlgraphics</groupId>
<artifactId>batik-constants</artifactId>
<version>1.13</version>
</dependency>
<dependency>
<groupId>org.apache.xmlgraphics</groupId>
<artifactId>batik-xml</artifactId>
<version>1.13</version>
</dependency>
<dependency>
<groupId>commons-lang</groupId>
<artifactId>commons-lang</artifactId>
<version>2.0</version>
</dependency>
<dependency>
<groupId>org.bluestemsoftware.open.maven.tparty</groupId>
<artifactId>xerces-impl</artifactId>
<version>2.9.0</version>
</dependency>
<dependency>
<groupId>jargs</groupId>
<artifactId>jargs</artifactId>
<version>1.0</version>
</dependency>
</dependencies>
<repositories>
<repository>
<id>wso2-maven2-repository</id>
<name>WSO2 Maven2 Repository</name>
<url>http://dist.wso2.org/maven2</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
<releases>
<enabled>true</enabled>
<updatePolicy>never</updatePolicy>
<checksumPolicy>fail</checksumPolicy>
</releases>
</repository>
</repositories>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<compilerArgs>
<arg>-Xlint:deprecation</arg>
<arg>-Xlint:unchecked</arg>
</compilerArgs>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-javadoc-plugin</artifactId>
<version>3.2.0</version>
<configuration>
<additionalparam>-Xdoclint:none</additionalparam>
<additionalOptions>-Xdoclint:none</additionalOptions>
<additionalJOption>-Xdoclint:none</additionalJOption>
</configuration>
<executions>
<execution>
<id>attach-javadocs</id>
<goals>
<goal>jar</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.3.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<archive>
<manifest>
<mainClass>ca.ualberta.stothard.cgview.CgviewIO</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
</plugins>
</build>
</project>
My java version is:
openjdk version "1.8.0_152-release"
OpenJDK Runtime Environment (build 1.8.0_152-release-1056-b12)
OpenJDK 64-Bit Server VM (build 25.152-b12, mixed mode)
Thanks

JDK9 and maven-jar-plugin

I just upgraded my Java8 project with the brand new official release of Java9.
The project uses a Maven plugin, org.apache.maven.plugins:maven-jar-plugin version 2.6. When I run mvn clean install I now get the following exception:
ERROR] Failed to execute goal org.apache.maven.plugins:maven-jar-plugin:2.6:jar (default-jar) on project my-test-utils: Execution default-jar of goal org.apache.maven.plugins:maven-jar-plugin:2.6:jar failed: An API incompatibility was encountered while executing org.apache.maven.plugins:maven-jar-plugin:2.6:jar: java.lang.ExceptionInInitializerError: null
[ERROR] -----------------------------------------------------
[ERROR] realm = plugin>org.apache.maven.plugins:maven-jar-plugin:2.6
[ERROR] strategy = org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy
[ERROR] urls[0] = file:/Users/jeanvaljean/.m2/repository/org/apache/maven/plugins/maven-jar-plugin/2.6/maven-jar-plugin-2.6.jar
[ERROR] urls[1] = file:/Users/jeanvaljean/.m2/repository/org/slf4j/slf4j-jdk14/1.5.6/slf4j-jdk14-1.5.6.jar
[ERROR] urls[2] = file:/Users/jeanvaljean/.m2/repository/org/slf4j/jcl-over-slf4j/1.5.6/jcl-over-slf4j-1.5.6.jar
[ERROR] urls[3] = file:/Users/jeanvaljean/.m2/repository/org/apache/maven/reporting/maven-reporting-api/2.2.1/maven-reporting-api-2.2.1.jar
[ERROR] urls[4] = file:/Users/jeanvaljean/.m2/repository/org/apache/maven/doxia/doxia-sink-api/1.1/doxia-sink-api-1.1.jar
[ERROR] urls[5] = file:/Users/jeanvaljean/.m2/repository/org/apache/maven/doxia/doxia-logging-api/1.1/doxia-logging-api-1.1.jar
[ERROR] urls[6] = file:/Users/jeanvaljean/.m2/repository/junit/junit/3.8.1/junit-3.8.1.jar
[ERROR] urls[7] = file:/Users/jeanvaljean/.m2/repository/commons-cli/commons-cli/1.2/commons-cli-1.2.jar
[ERROR] urls[8] = file:/Users/jeanvaljean/.m2/repository/org/codehaus/plexus/plexus-interactivity-api/1.0-alpha-4/plexus-interactivity-api-1.0-alpha-4.jar
[ERROR] urls[9] = file:/Users/jeanvaljean/.m2/repository/backport-util-concurrent/backport-util-concurrent/3.1/backport-util-concurrent-3.1.jar
[ERROR] urls[10] = file:/Users/jeanvaljean/.m2/repository/org/sonatype/plexus/plexus-sec-dispatcher/1.3/plexus-sec-dispatcher-1.3.jar
[ERROR] urls[11] = file:/Users/jeanvaljean/.m2/repository/org/sonatype/plexus/plexus-cipher/1.4/plexus-cipher-1.4.jar
[ERROR] urls[12] = file:/Users/jeanvaljean/.m2/repository/org/codehaus/plexus/plexus-interpolation/1.11/plexus-interpolation-1.11.jar
[ERROR] urls[13] = file:/Users/jeanvaljean/.m2/repository/org/apache/maven/maven-archiver/2.6/maven-archiver-2.6.jar
[ERROR] urls[14] = file:/Users/jeanvaljean/.m2/repository/org/apache/maven/shared/maven-shared-utils/0.7/maven-shared-utils-0.7.jar
[ERROR] urls[15] = file:/Users/jeanvaljean/.m2/repository/com/google/code/findbugs/jsr305/2.0.1/jsr305-2.0.1.jar
[ERROR] urls[16] = file:/Users/jeanvaljean/.m2/repository/org/codehaus/plexus/plexus-utils/3.0.20/plexus-utils-3.0.20.jar
[ERROR] urls[17] = file:/Users/jeanvaljean/.m2/repository/org/codehaus/plexus/plexus-archiver/2.9/plexus-archiver-2.9.jar
[ERROR] urls[18] = file:/Users/jeanvaljean/.m2/repository/org/codehaus/plexus/plexus-io/2.4/plexus-io-2.4.jar
[ERROR] urls[19] = file:/Users/jeanvaljean/.m2/repository/commons-io/commons-io/2.2/commons-io-2.2.jar
[ERROR] urls[20] = file:/Users/jeanvaljean/.m2/repository/org/apache/commons/commons-compress/1.9/commons-compress-1.9.jar
[ERROR] Number of foreign imports: 1
[ERROR] import: Entry[import from realm ClassRealm[maven.api, parent: null]]
[ERROR]
Any hint on how to solve this?
I'm using Maven 3.3.9. mvn -version outputs:
Apache Maven 3.3.9 (bb52d8502b132ec0a5a3f4c09453c07478323dc5; 2015-11-10T17:41:47+01:00)
Maven home: /Users/jeanvaljean/Applications/maven/apache-maven-3.3.9
Java version: 9, vendor: Oracle Corporation
Java home: /Library/Java/JavaVirtualMachines/jdk-9.jdk/Contents/Home
Default locale: en_IT, platform encoding: UTF-8
OS name: "mac os x", version: "10.12.3", arch: "x86_64", family: "mac"
The module that is failing is actually the first child module of the parent pom. It is surprisingly empty:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
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>1.5.7.RELEASE</version>
</parent>
<groupId>my.group</groupId>
<artifactId>my-parent</artifactId>
<version>0.1.0-SNAPSHOT</version>
<packaging>pom</packaging>
<modules>
<module>test-utils</module>
<module>commons</module>
<module>validation</module>
</modules>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>9</java.version>
<tomcat.version>8.5.5</tomcat.version>
<unit-tests.skip>true</unit-tests.skip>
<integration-tests.skip>true</integration-tests.skip>
<!-- PLUGINS -->
<maven-compiler-plugin>3.6.2</maven-compiler-plugin>
<maven-surefire-plugin>2.20.1</maven-surefire-plugin>
<nexus-staging-maven-plugin>1.6.8</nexus-staging-maven-plugin>
<maven-source-plugin>3.0.1</maven-source-plugin>
<maven-javadoc-plugin>3.0.0-M1</maven-javadoc-plugin>
<maven-gpg-plugin>1.6</maven-gpg-plugin>
<versions-maven-plugin>2.4</versions-maven-plugin>
<maven-scm-plugin>1.9.5</maven-scm-plugin>
</properties>
<prerequisites>
<maven>3.0.4</maven>
</prerequisites>
<dependencies>
<!-- SPRING BOOT -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-hystrix</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.retry</groupId>
<artifactId>spring-retry</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.2</version>
<configuration>
<source>9</source>
<target>9</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
<configuration>
<skip>true</skip>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<configuration>
<excludes>
<exclude>**/*AcceptanceTest.java</exclude>
<exclude>**/*IT.java</exclude>
</excludes>
</configuration>
<executions>
<execution>
<id>integration-test</id>
<goals>
<goal>test</goal>
</goals>
<phase>integration-test</phase>
<configuration>
<excludes>
<exclude>none</exclude>
</excludes>
<includes>
<include>**/*IT.java</include>
</includes>
</configuration>
</execution>
<execution>
<id>acceptance-test</id>
<goals>
<goal>test</goal>
</goals>
<phase>verify</phase>
<configuration>
<excludes>
<exclude>none</exclude>
</excludes>
<includes>
<include>**/*AcceptanceTest.java</include>
</includes>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.jacoco</groupId>
<artifactId>jacoco-maven-plugin</artifactId>
<version>0.7.5.201505241946</version>
<executions>
<execution>
<id>default-prepare-agent</id>
<goals>
<goal>prepare-agent</goal>
</goals>
</execution>
<execution>
<id>default-check</id>
<phase>prepare-package</phase>
<goals>
<goal>report</goal>
<goal>check</goal>
</goals>
<configuration>
<rules>
<rule>
<element>CLASS</element>
<excludes>
<!--<exclude>it.ozimov</exclude>-->
</excludes>
<limits>
<limit>
<counter>BRANCH</counter>
<value>COVEREDRATIO</value>
<minimum>0</minimum>
</limit>
<limit>
<counter>LINE</counter>
<value>COVEREDRATIO</value>
<minimum>0</minimum>
</limit>
</limits>
</rule>
</rules>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>versions-maven-plugin</artifactId>
<version>2.3</version>
<configuration>
<generateBackupPoms>false</generateBackupPoms>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.4.1</version>
<dependencies>
<dependency>
<groupId>org.codehaus.plexus</groupId>
<artifactId>plexus-archiver</artifactId>
<version>2.4.4</version>
</dependency>
</dependencies>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.6</version>
<dependencies>
<dependency>
<groupId>org.codehaus.plexus</groupId>
<artifactId>plexus-archiver</artifactId>
<version>2.4.4</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
</project>

The chances are mostly of an incompatible maven-plugin version in your module. You could try to update the plugin configuration in the parent module to the following and test:
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.7.0</version>
<configuration>
<source>1.9</source>
<target>1.9</target>
<jdkToolchain>
<version>9</version>
</jdkToolchain>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.0.2</version>
</plugin>
</plugins>
</build>
For the list of compatible versions of all the plugins, do refer to Maven#Java9+Jigsaw

I had the latest maven version 3.6.3. But I realized there is a mismatch in the java version set in my environment path config to the one installed in my IDE (IntelliJ).
I configured to the latest JDK version (for 1.8) in my IDE to 1.8.0_265
I set my environment path to the same version
You can configure JAVA_HOME, JRE_HOME, JDK_HOME here. Also, make sure the path is added.
Reference on how to set environment variables: https://stackoverflow.com/a/26640589/2889297
Maven homepage gives you a high-level idea on what should be the compatible java version https://maven.apache.org/install.html
Note: After updating the environment path and before running mvn clean install, make sure the version is correctly reflected in the IDE terminal. You will have to close and reopen your IDE for the changes to be reflected.

compilation failure for spring boot application with java 9 and maven

I am trying to build spring-boot application that uses java-9 and would be deployed to heroku. As a build tool I use maven.
I generated spring boot 1.5 application using initializr. I added heroku specific files and added toolchains.xml to .m2 repository for maven-compiler-plugin.
My pom.xml looks like this
<?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.lapots.breed.platform.cloud</groupId>
<artifactId>java-cloud-sample</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>java-cloud-sample</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.6.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.9</java.version>
<maven.compiler.source>1.9</maven.compiler.source>
<maven.compiler.target>1.9</maven.compiler.target>
<maven.compiler.release>9</maven.compiler.release>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
<scope>runtime</scope>
</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>build-info</goal>
</goals>
<configuration>
<additionalProperties>
<encoding.source>${project.build.sourceEncoding}</encoding.source>
<encoding.reporting>${project.reporting.outputEncoding}</encoding.reporting>
<java.source>${maven.compiler.source}</java.source>
<java.target>${maven.compiler.target}</java.target>
</additionalProperties>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.0</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-toolchains-plugin</artifactId>
<version>1.1</version>
<configuration>
<toolchains>
<jdk>
<version>1.9</version>
<vendor>oracle</vendor>
</jdk>
</toolchains>
</configuration>
<executions>
<execution>
<goals>
<goal>toolchain</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
When I try to compiler project using mvn clean package I get the error
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] javac: invalid flag: -Xmodule:null
Usage: javac <options> <source files>
use --help for a list of possible options
[INFO] 1 error
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.031 s
[INFO] Finished at: 2017-08-30T21:08:25+03:00
[INFO] Final Memory: 20M/309M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.6.0:testCompile (default-testCompile) on
project java-cloud-sample: Compilation failure
[ERROR] javac: invalid flag: -Xmodule:null
[ERROR] Usage: javac <options> <source files>
[ERROR] use --help for a list of possible options
[ERROR]
[ERROR]
[ERROR] -> [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/MojoFailureException
module-info looks like this
module com.lapots.breed.platform.cloud.javacloudsample {
requires spring.boot;
}
What is the problem? Project available here
github repository

maven-compiler-plugin 3.6.0 is based on the first signature of module-info.class, which has changed a couple of times. It is not compatible with current Java 9 signature. You should use 3.6.2 when using most recent versions of JDK 9.

Looks like your toolchains.xml does not include an entry for Java 9. Try this:
<toolchain>
<type>jdk</type>
<provides>
<version>1.9</version>
<vendor>oracle</vendor>
</provides>
<configuration>
<jdkHome>/path/to/jdk/9</jdkHome>
</configuration>
</toolchain>

Rightly pointed out by #Robert you need to update your maven-compiler-plugin. To add to it, also as stated in the Maven/Jigsaw+9 over the maven plugins. The minimum compatible version of maven-compiler-plugin with current jdk-9+181 is 3.6.2 which can be used as :
<!--Minimum compatible version required-->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.2</version>
<configuration>
<jdkToolchain>
<version>9</version>
</jdkToolchain>
</configuration>
</plugin>
And to quote from one of the examples of maven-compiler-plugin with module-info.java here:
For projects that want to be compatible with older versions of Java
(i.e 1.8 or below), but also want to provide a module-info.java for
Java 9 projects must be aware that they need to call javac twice: the
module-info.java must be compiled with release=9, while the rest of
the sources must be compiled with a lower version of source/target.
which can be achieved using (JAVA_HOME set as 1.8.x) :
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.2</version>
<executions>
<execution>
<id>default-compile</id>
<configuration>
<!-- compile everything to ensure module-info contains right entries -->
<!-- required when JAVA_HOME is JDK 8 or below -->
<jdkToolchain>
<version>9</version>
</jdkToolchain>
<release>9</release>
</configuration>
</execution>
<execution>
<id>base-compile</id>
<goals>
<goal>compile</goal>
</goals>
<!-- recompile everything for target VM except the module-info.java -->
<configuration>
<excludes>
<exclude>module-info.java</exclude>
</excludes>
</configuration>
</execution>
</executions>
<!-- defaults for compile and testCompile -->
<configuration>
<!-- jdkToolchain required when JAVA_HOME is JDK 9 or above -->
<jdkToolchain>
<version>[1.5,9)</version>
</jdkToolchain>
<source>1.5</source>
<target>1.5</target>
</configuration>
</plugin>
Few things to note there though are:
... you will need at least Maven 3.3.1 to specify a custom
jdkToolchain in your plugin configuration
Or you can also configure the JAVA_HOME as /jdk9/Contents/Home/bin and use the following configuration:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.6.2</version>
<executions>
<execution>
<id>default-compile</id>
<configuration>
<!-- compile everything to ensure module-info contains right entries -->
<release>9</release>
</configuration>
</execution>
<execution>
<id>base-compile</id>
<goals>
<goal>compile</goal>
</goals>
<!-- recompile everything for target VM except the module-info.java -->
<configuration>
<excludes>
<exclude>module-info.java</exclude>
</excludes>
</configuration>
</execution>
</executions>
<!-- defaults for compile and testCompile -->
<configuration>
<!-- Only required when JAVA_HOME isn't at least Java 9 and when haven't configured the maven-toolchains-plugin -->
<jdkToolchain>
<version>9</version>
</jdkToolchain>
<release>6</release>
</configuration>
</plugin>