title: Unable to import ShadowJar plugin for Gradle in Intellij
body: <p>I'm trying to set up the shadow jar plugin for use in my Gradle project.  As according to the instructions, I'm importing it like so:</p>
  
  <pre><code>plugins {
      id 'com.github.johnrengelman.shadow' version '4.0.2'
  }
  </code></pre>
  
  <p>However, when the build starts, I get the following error:</p>
  
  <pre><code>Plugin [id: 'com.github.johnrengelman.shadow', version: '4.0.2'] was not found in any of the following sources:
  
  - Gradle Core Plugins (plugin is not in 'org.gradle' namespace)
  - Plugin Repositories (could not resolve plugin artifact 'com.github.johnrengelman.shadow:com.github.johnrengelman.shadow.gradle.plugin:4.0.2')
    Searched in the following repositories:
      Gradle Central Plugin Repository
  </code></pre>
  
  <p>When investigating the stack trace in configure build, I also find this:</p>
  
  <pre><code>org.gradle.internal.resource.transport.http.HttpRequestException: Could not HEAD 'https://plugins.gradle.org/m2/com/github/johnrengelman/shadow/com.github.johnrengelman.shadow.gradle.plugin/4.0.2/com.github.johnrengelman.shadow.gradle.plugin-4.0.2.pom'.
  
  Caused by: org.apache.http.conn.HttpHostConnectException: Connect to plugins.gradle.org:443 [plugins.gradle.org/104.16.175.166, plugins.gradle.org/104.16.173.166, plugins.gradle.org/104.16.172.166, plugins.gradle.org/104.16.171.166, plugins.gradle.org/104.16.174.166] failed: Connection timed out: connect
  </code></pre>
  
  <p>Based on this, I'm assuming that there is something wrong between my machine and the plugins repository.  I'm working behind a corporate proxy, so I'm wondering if there is any workaround?</p>
  
  <p>Edit:  Here is the structure for the code of my repository declaration. Due to security concerns, I'd rather not share the actual url:</p>
  
  <pre><code>repositories {
      maven { url 'corporate.repo.url.here:port' }
  }
  </code></pre>
  
  <p>Upon double checking, it seems that the repository is correct, and so the plugin should be downloaded to my local Maven repository.  It was not, which I assume has to due with my migration to Gradle. Are there any settings in Gradle to handle this?</p>