title: Unable to download plugin for eclipse
body: <p>I am trying to download kotlin plugin for eclipse. I am able to connect to eclipse marketplace, but when i try to download it, I get an error: </p>
  
  <pre><code>Unable to read repository at 
  https://dl.bintray.com/jetbrains/kotlin/eclipse-plugin/last/content.xml.
  
  sun.security.validator.ValidatorException: PKIX path building failed: 
  sun.security.provider.certpath.SunCertPathBuilderException: 
  unable to find valid certification path to requested target
  </code></pre>
  
  <p>I am behind a firewall and proxy settings are configured. I downloaded a certificate from this website and added it to keytool but the error is still the same. How I can resolve this error or install this plugin manually?</p>