Could not calculate build plan: Plugin org.apache.maven.plugins:maven-jar-plugin:2.3.2 or one of its dependencies could not be resolved

Question

I got the following error message when I tried to create a Maven project in eclipse. Many have posted about proxies in settings.xml file and also flush the .m2 folder forcin

Answer 1

There could be multiple reasons, i fixed with following steps:

1. delete .m2 folder and re launch eclipse. (Find m2 folder in windows: c:\Users\Your_User_Name\ .m2 or to search in Mac : ~/.m2
2. make sure settings.xml is configured as #JustinBieber mentioned.
3. provide settings.xml path in eclipse (windows->preferences->maven->user settings) User Settings must locate settings.xml file.

save changes and relaunch the eclipse..!! it should work.

Answer 2

run:

mvn -U dependency:go-offline

It works for me.

Answer 3

I solved it now. However it only is solved in Netbeans. Not sure why eclipse still won't take the settings.xml that is changed. The solution is however to remove/comment the User/Password param in settings.xml

Before:

<proxies>
    <proxy>
      <id>optional</id>
      <active>true</active>
      <protocol>http</protocol>
      <username>proxyuser</username>
      <password>proxypass</password>
      <host>proxyserver.company.com</host>
      <port>8080</port>
      <nonProxyHosts>local.net|some.host.com</nonProxyHosts>
    </proxy>
  </proxies> 

After:

<proxies>
    <proxy>
      <id>optional</id>
      <active>true</active>
      <protocol>http</protocol>
      <host>proxyserver.company.com</host>
      <port>8080</port>
      <nonProxyHosts>local.net|some.host.com</nonProxyHosts>
    </proxy>
  </proxies> 

Answer 4

I also had the same problem. I used next way:

1.Added settings.xml file (~/.m2/settings.xml) with next content

<proxies>
   <proxy>
      <active>true</active>
      <protocol>http</protocol>
      <host>qq-proxya</host>
      <port>8080</port>
      <username>user</username>
      <password>passw</password>
      <nonProxyHosts>www.google.com|*.example.com</nonProxyHosts>
    </proxy>
  </proxies>

3. Using cmd go to folder with my project and wrote mvn clean and after that mvn install !

4. After that updated project in the Eclipse(Alt + F5) or right click on project -> Maven -> Update project

P.S. after that, when I add new dependency to my project I have to compile project using cmd(mvn compile). Because if I do it using eclipse plugin, I get error connecting with proxy connection.

Answer 5

Excellent i got solution:
Just clearing (.m2) complete folder and starting a new maven project problem solved for me.

Note:: .m2 folder located in os installed disk only.
If you want the exact location, check in Eclipse:
Eclipse-->window-->preferences-->maven-->user settings
There local repository path is for .m2
Delete entire .m2 folder and restart your eclipse.

Answer 6

Whenever if you get this error please delete .m2 repository from local drive C:\Users\user and delete .m2 from there. The reason is this is existing repository used by different workspace so not allowing new application to create