title: In Java, it's possible Singleton per thread?
body: <p>Using threads, I have a principal class (<code>SlaveCrawler</code>) that instantiates three classes(<code>Downloader, ContentAnalyzer, URLAnalyzer</code>) , which are dependent on each other.</p>
  
  <p><code>SlaveCrawler</code> uses <code>Downloader</code> and <code>URLAnalyzer</code></p>
  
  <p><code>Downloader</code> uses <code>ContentAnalyzer</code> and <code>URLAnalyzer</code></p>
  
  <p><code>ContentAnalyzer</code> uses <code>URLAnalyzer</code></p>
  
  <p>I want only one instance of each class. If I use <code>Singleton</code>, I can get this, but working with threads, I will have 20 <code>SlaveCrawlers</code>(example), so I want 20 <code>URLAnalyzer</code>.</p>
  
  <p>It's possible make this using <code>Singleton</code> or I need other way?</p>