Plugin org.apache.maven.plugins:maven-clean-plugin:2.5 or one of its dependencies could not be resolved

Your debug output indicates that Clean is the first thing that it's trying to run, so I'm guessing it's failing to download any plugins from central.

First off, see if you can download the plugin jar directly in a web browser: http://repo1.maven.org/maven2/org/apache/maven/plugins/maven-clean-plugin/2.5/maven-clean-plugin-2.5.jar

If that works then your web browser has connectivity to central but maven doesn't. That suggests to me that your web browser is using a proxy that maven isn't configured to use.

Maven proxy settings are described in depth here. To simplify that a little fill this out (replace the protocol/host/port with the values from your internet settings) and put it in the <settings> tag of your maven settings.xml file:

<proxies>
  <proxy>
    <id>proxy</id>
    <active>true</active>
    <protocol>http</protocol>
    <host>proxy.example.com</host>
    <port>8080</port>
  </proxy>
</proxies>

The error is due to maven official repository being not accessible. This repo (https://repo.maven.apache.org/maven2/) is not accessible so follow these steps:

1. Firstly delete your /home/user/.m2 folder
2. create .m2 folder at user home and repository folder within .m2
3. copy the default settings.xml to .m2 folder
4. Change mirrors as follows in the settings.xml as shown in below snap mirror_settings

<mirrors>
  <mirror>
    <id>UK</id>
    <name>UK Central</name>
    <url>http://uk.maven.org/maven2</url>
    <mirrorOf>central</mirrorOf>
  </mirror>
</mirrors>

5. Execute the mvn clean commands now .....

It might be that you are forgetting to specify the settings which was the case with me.

Try:

mvn clean install -s settings_file.xml