title: Eclipse cleanup - what are the ".index" files - can I safely delete them?
body: <p>Trying to reduce the size of my (DB synced) workspace - realized that the folder </p>
  
  <pre><code>${workspace_loc}\.metadata\.plugins\org.eclipse.jdt.core
  </code></pre>
  
  <p>was taking ~35 Mbytes - the contents of the folder are <code>.index</code> files (which take the most space) and some others (which are a couple Kb worth) :</p>
  
  <pre><code>[0-9]*\.index
  externalLibsTimeStamps
  indexNamesMap.txt
  invalidArchivesCache
  javaLikeNames.txt
  nonChainingJarsCache
  participantsIndexNames.txt
  savedIndexNames.txt
  variablesAndContainers.dat
  </code></pre>
  
  <p>I can't seem to be able to find docs on those. Can I safely delete them ? Can you point me to some docs on the JDT plugin folders/files contained in <code>${workspace_location}\.metadata\</code> directory ?<br>
  Is there any way via the gui to clean up the caches (preferably periodically) ?</p>
  
  <p>PS : I 'm on Kepler if this makes a difference
  PS2 : links to docs may be links to code comments and such</p>