title: How to set eclipse preferences use plugin?
body: <p>Now I'm using python to change settings files under <code>.metadata/</code> in my workspace.I need find every line needed in these files beacuase I don't want any unnecessary content.</p>
  
  <p>For example , if I want set tab's width be 4. I need change the file</p>
  
  <pre><code>.metadata/.plugins/org.eclipse.core.runtime/.settings/org.eclipse.ui.editors.prefs
  </code></pre>
  
  <p>in workspace and add a line following in it , not simply copy the settings file:</p>
  
  <pre><code>tabWidth=4
  </code></pre>
  
  <p><strong>So I want to know</strong> : Can I set this value by java code in eclipse plugin? If it can, please give me related classes :-)</p>
  
  <p><strong>And</strong>, does it more complex than python's method?</p>