title: How can I upgrade Eclipse Luna to Mars from Eclipse?
body: <p>I tried upgrading from Luna to Mars by following the instructions here: <a href="https://wiki.eclipse.org/FAQ_How_do_I_upgrade_Eclipse%3F">https://wiki.eclipse.org/FAQ_How_do_I_upgrade_Eclipse%3F</a></p>
  
  <p>I added the Mars repository <a href="http://download.eclipse.org/releases/mars">http://download.eclipse.org/releases/mars</a> as an update site and then did check for updates. But I get the exception </p>
  
  <pre><code>An error occurred while collecting items to be installed
  session context was:(profile=epp.package.java, phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=, action=).
  No repository found containing: osgi.bundle,org.eclipse.epp.package.java,4.5.0.20150603-1639
  No repository found containing: binary,epp.package.java.executable.gtk.linux.x86_64,4.5.0.20150603-1639
  No repository found containing: org.eclipse.update.feature,org.eclipse.epp.package.common.feature,4.5.0.20150603-1639
  No repository found containing: org.eclipse.update.feature,org.eclipse.epp.package.java.feature,4.5.0.20150603-1639
  </code></pre>
  
  <p>How can I fix this?</p>