Plugin not found for 'jetty' prefix in current project and in plugin groups (local, central)

Question

To easily run my web application, I decided to add Jetty to my single POM file.

Following the official documentation , I added this to my <plugins>:

  <plugin>
    <groupId>org.eclipse.jetty</groupId>
    <artifactId>jetty-maven-plugin</artifactId>
    <version>9.4.0-SNAPSHOT</version>
  </plugin>

PROBLEM : mvn jetty:runfailed:

$ mvn jetty:start
[INFO] Scanning for projects...
[WARNING] The POM for org.eclipse.jetty:jetty-maven-plugin:jar:9.4.0-SNAPSHOT is missing, no dependency information available
[WARNING] Failed to retrieve plugin descriptor for org.eclipse.jetty:jetty-maven-plugin:9.4.0-SNAPSHOT: Plugin org.eclipse.jetty:jetty-maven-plugin:9.4.0-SNAPSHOT or one of its dependencies could not be resolved: Could not find artifact org.eclipse.jetty:jetty-maven-plugin:jar:9.4.0-SNAPSHOT
Downloading: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-metadata.xml
Downloading: https://repo.maven.apache.org/maven2/org/codehaus/mojo/maven-metadata.xml
Downloaded: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-metadata.xml (13 KB at 2.1 KB/sec)
Downloaded: https://repo.maven.apache.org/maven2/org/codehaus/mojo/maven-metadata.xml (20 KB at 3.2 KB/sec)
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 7.013 s
[INFO] Finished at: 2016-08-17T16:49:28+09:00
[INFO] Final Memory: 14M/307M
[INFO] ------------------------------------------------------------------------
[ERROR] No plugin found for prefix 'jetty' in the current project and in the plugin groups [org.apache.maven.plugins, org.codehaus.mojo] available from the repositories [local (/home/nico/.m2/repository), central (https://repo.maven.apache.org/maven2)] -> [Help 1]

Another approach at https://mvnrepository.com/artifact/org.eclipse.jetty/jetty-maven-plugin/9.4.0.M0 suggests adding this to <dependencies>:

            <dependency>
                <groupId>org.eclipse.jetty</groupId>
                <artifactId>jetty-maven-plugin</artifactId>
                <version>9.4.0.M0</version>
            </dependency>

It doesn't help either, mvn jetty:startsays:

[ERROR] No plugin found for prefix 'jetty' in the current project and in the plugin groups [org.apache.maven.plugins, org.codehaus.mojo] available from the repositories [local (/home/nico/.m2/repository), central (https://repo.maven.apache.org/maven2)] -> [Help 1]

I deleted the folder .m2and allowed Maven to recreate it, no better. I do not have settings.xmlin ~/.m2, but the contents are ~/.m2/repository/org/eclipse/jetty/jetty-maven-plugin/9.4.0.M0/:

-rw-rw-r-- 1 nico nico 101524  8月 24 17:29 jetty-maven-plugin-9.4.0.M0.jar
-rw-rw-r-- 1 nico nico     40  8月 24 17:29 jetty-maven-plugin-9.4.0.M0.jar.sha1
-rw-rw-r-- 1 nico nico   5526  8月 24 17:28 jetty-maven-plugin-9.4.0.M0.pom
-rw-rw-r-- 1 nico nico     40  8月 24 17:28 jetty-maven-plugin-9.4.0.M0.pom.sha1
-rw-rw-r-- 1 nico nico    215  8月 24 17:29 _remote.repositories

. . , Maven (mortbay, codehaus), , Jetty Eclipse, <plugin> .

Answer 1

9.4.0-SNAPSHOT. ( ).

dependency , plugin. , , - , , .

:

• dependency on jetty-maven-plugin

• version plugin , .
  :

  <plugin>
      <groupId>org.eclipse.jetty</groupId>
      <artifactId>jetty-maven-plugin</artifactId>
      <version>9.4.0.M0</version>
  </plugin>
  

Answer 2

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
                      http://maven.apache.org/xsd/settings-1.0.0.xsd">
  <localRepository>${user.home}/.m2/repository</localRepository>
  <interactiveMode>true</interactiveMode>
  <usePluginRegistry>false</usePluginRegistry>
  <offline>false</offline>
  <pluginGroups>
    <pluginGroup>org.mortbay.jetty</pluginGroup>
  </pluginGroups>
</settings>

.