java - How to fix [Error] realm = plugin>org.apache.maven.plugins:maven-compiler-plugin:3.x (Happened while working on Spring Boot) -

problem

i decided spring boot hello word example work java 1.8 annoying dependency issues. in answer section explain solved problem hints on how bring on machine date. error getting was:

[error] realm =    plugin>org.apache.maven.plugins:maven-compiler-plugin:3.x [error] strategy = org.codehaus.plexus.classworlds.strategy.selffirststrategy [error] urls[0] = file:/users/xxx/.m2/repository/org/apache/maven/plugins/maven-compiler-plugin/3.1/maven-compiler-plugin-3.1.jar [error] urls[1] = file:/users/xxx/.m2/repository/org/codehaus/plexus/plexus-utils/1.5.1/plexus-utils-1.5.1.jar [error] urls[2] = file:/users/xxx/repository/org/apache/maven/shared/maven-shared-utils/0.1/maven-shared-utils-0.1.jar [error] urls[3] = file:/users/xxx/repository/com/google/code/findbugs/jsr305/2.0.1/jsr305-2.0.1.jar [error] urls[4] = file:/users/xxx/.m2/repository/org/apache/maven/shared/maven-shared-incremental/1.1/maven-shared-incremental-1.1.jar [error] urls[5] = file:/users/xxx/.m2/repository/org/codehaus/plexus/plexus-component-annotations/1.5.5/plexus-component-annotations-1.5.5.jar [error] urls[6] = file:/users/xxx/.m2/repository/org/codehaus/plexus/plexus-compiler-api/2.2/plexus-compiler-api-2.2.jar [error] urls[7] = file:/users/xxx/.m2/repository/org/codehaus/plexus/plexus-compiler-manager/2.2/plexus-compiler-manager-2.2.jar [error] urls[8] = file:/users/xxx/.m2/repository/org/codehaus/plexus/plexus-compiler-javac/2.2/plexus-compiler-javac-2.2.jar [error] urls[9] = file:/users/xxx/.m2/repository/org/apache/xbean/xbean-reflect/3.4/xbean-reflect-3.4.jar [error] urls[10] = file:/users/xxx/.m2/repository/log4j/log4j/1.2.12/log4j-1.2.12.jar [error] urls[11] = file:/users/xxx/.m2/repository/commons-logging/commons-logging-api/1.1/commons-logging-api-1.1.jar [error] urls[12] = file:/users/xxx/.m2/repository/com/google/collections/google-collections/1.0/google-collections-1.0.jar [error] urls[13] = file:/users/xxx/.m2/repository/junit/junit/3.8.2/junit-3.8.2.jar 

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solutions didn't work

a lot of threads suggesting removing ~/.m2/ repositories here did not solve problem.

some others said due java 1.8 , works them java 1.7! couldn't believe them did not make sense. , wanted simple example work java 8.

solution summary

it dependency conflict had nothing java version or repositories under .m2 folder me.

the source of error dependency conflict caused plugin>org.apache.maven.plugins:maven-compiler-plugin:3.x.

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other related sources

other questions on stackoverflow similar didn't solve problem spring boot follows:

1- maven-build-error-failed-to-execute-goal-missing-a-class

2- failed-to-execute-goal-org-apache-maven-pluginsmaven-compiler-plugin2-3-2comp

3- maven-release-plugin-issue-failed-to-execute-goal-org-apache-maven-pluginsmav

4- maven-archetype-problem

solution

as mentioned, source of error dependency conflict caused plugin>org.apache.maven.plugins:maven-compiler-plugin:3.x. based on comment made in cases specifying java version through <properties><java.version>1.8</java.version></properties> solves problem (based on guide here).

however in case (checkout specs) specifying maven compiler plugin , through following code solved problem:

<plugin>     <artifactid>maven-compiler-plugin</artifactid>     <version>2.3.2</version>     <configuration>         <source>1.8</source>         <target>1.8</target>     </configuration> </plugin> 

specs

• java 1.8_45
• maven 3.3.3
• os x yosemite

files

basically had specify maven-compiler-plugin in pom.xml (see below).

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>helloworld</artifactid>     <version>0.1.0</version>     <!-- inherit defaults spring boot -->     <parent>         <groupid>org.springframework.boot</groupid>         <artifactid>spring-boot-starter-parent</artifactid>         <version>1.2.2.release</version>     </parent>     <dependencies>         <dependency>             <groupid>org.springframework.boot</groupid>             <artifactid>spring-boot-starter-web</artifactid>         </dependency>      </dependencies>     <build>         <plugins>              <plugin>                 <artifactid>maven-compiler-plugin</artifactid>                 <version>2.3.2</version>                 <configuration>                     <source>1.8</source>                     <target>1.8</target>                 </configuration>             </plugin>             <plugin>                 <groupid>org.springframework.boot</groupid>                 <artifactid>spring-boot-maven-plugin</artifactid>             </plugin>          </plugins>     </build> </project> 

samplecontoroller.java

import org.springframework.boot.*; import org.springframework.boot.autoconfigure.*; import org.springframework.web.bind.annotation.*;  @restcontroller @enableautoconfiguration public class samplecontroller {      @requestmapping("/")     string home() {         return "hello world!";     }      public static void main(string[] args) throws exception {         springapplication.run(samplecontroller.class, args);     } } 

project folder structure

just follow maven standard structure.

hint please feel free give me feedback in comments if solved problem, or if faced other issues.