title: maven-enforcer-plugin issue while creating org.jenkins-ci.plugins in eclipse
body: <p>I try to get a minimal empty jenkins plugin to compile and show in a jetty jenkins.</p>
  
  <p>I created a new Java Project and made it into a maven project.
  <code>Right Click -&gt; Configure -&gt; Into Maven</code>.</p>
  
  <p>My problem stems from the Parent.</p>
  
  <pre><code>Group Id: org.jenkins-ci.plugins 
  Artifact Id: plugin
  Version: 3.9
  </code></pre>
  
  <p>When I execute the Goal <code>RunAs -&gt; Maven -&gt; Install</code> I get an error.
  The error string contains:</p>
  
  <pre><code>maven-enforcer-plugin:3.0.0-M1:enforce failed: Unknown JDK version given. Should be something like "1.7"
  </code></pre>
  
  <p>I Installed multiple Java Versions in the machine so I should have some to choose from. I tried to set a deifferent JRE dependency in the Project Propererties with no effect.</p>
  
  <p>A bit further up there is a relevant output:</p>
  
  <pre><code>[INFO] --- maven-enforcer-plugin:3.0.0-M1:display-info (display-info) @ ManualTestingMapper ---
  [INFO] Maven Version: 3.3.9
  [INFO] JDK Version: 1.8.0_162 normalized as: 1.8.0-162
  [INFO] OS Info: Arch: amd64 Family: windows Name: windows 7 Version: 6.1
  [INFO] 
  [INFO] --- maven-enforcer-plugin:3.0.0-M1:enforce (display-info) @ ManualTestingMapper ---
  </code></pre>
  
  <p>My Windows environment has <code>JAVA_HOME=c:\Program Files (x86)\Java\jre8u152</code> and the PATH also points in that general direction.</p>
  
  <p>How does one fix this in eclipse?
  I would need to change the JDK version on a per project level.
  I can not find anything useful using google - those were all dead ends fir me.</p>
  
  <p>EDIT: 
  I should mention that changing the Project Facets to Java 1.7 gives the enforcer output:</p>
  
  <pre><code>[INFO] --- maven-enforcer-plugin:3.0.0-M1:display-info (display-info) @ ManualTestingMapper ---
  [INFO] Maven Version: 3.3.9
  [INFO] JDK Version: 1.7.0_80 normalized as: 1.7.0-80
  [INFO] OS Info: Arch: amd64 Family: windows Name: windows 7 Version: 6.1
  [INFO] 
  [INFO] --- maven-enforcer-plugin:3.0.0-M1:enforce (display-info) @ ManualTestingMapper ---
  </code></pre>
  
  <p>The error about needing JDK 1.7 is still the same though.</p>
  
  <p>EDIT:
  Here is my POM, I updated the IDs to something neutral.</p>
  
  <pre><code>&lt;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"&gt;
    &lt;modelVersion&gt;4.0.0&lt;/modelVersion&gt;
    &lt;groupId&gt;SOGrouID&lt;/groupId&gt;
    &lt;artifactId&gt;SOArtifactID&lt;/artifactId&gt;
    &lt;version&gt;0.0.1-SNAPSHOT&lt;/version&gt;
    &lt;name&gt;SOName&lt;/name&gt;
    &lt;description&gt;SOName is a Stackoverflow Example.&lt;/description&gt;
    &lt;parent&gt;
      &lt;groupId&gt;org.jenkins-ci.plugins&lt;/groupId&gt;
      &lt;artifactId&gt;plugin&lt;/artifactId&gt;
      &lt;version&gt;3.9&lt;/version&gt;
    &lt;/parent&gt;
  &lt;/project&gt;
  </code></pre>
  
  <p>The parent POM contains</p>
  
  <pre><code>&lt;requireJavaVersion&gt;
  &lt;version&gt;[1.8.0,)&lt;/version&gt;
  &lt;/requireJavaVersion&gt;
  </code></pre>
  
  <p>which raises more questions than it answers.
  The whole parent POM can be inspected <a href="https://github.com/jenkinsci/plugin-pom/blob/plugin-3.9/pom.xml" rel="nofollow noreferrer">on github.</a></p>
  
  <p>EDIT: Running the maven goal Install -X gives the exception type:</p>
  
  <pre><code>java.lang.IllegalArgumentException: Unknown JDK version given. Should be something like "1.7"
  </code></pre>
  
  <p>I guess "1.7" could be meant as a format example. If that is so then the plugin may be presented with an incomprehensible format string of sorts?</p>