title: Spring equivalent to EJB Singleton Session Bean's concurrency guarantees
body: <p>I'm in the process of converting a Java EE 6 application to Spring + non-EE Container (for example Jetty) and I'm looking for an alternative to Java EE's Singleton Session Bean (usually implemented by using the <code>@Singleton</code> annotation).</p>
  
  <p>The <em>Singleton</em> aspect of it is easily handled by Spring. But the <code>@Singleton</code> annotation also implies concurrency guarantees: By default, all methods of a Singleton Session Bean are strictly serialized by a write-lock. (The behavior is can be changed by using the <code>@Lock</code>annotation.)</p>
  
  <p>Is there any  (ideally drop-in) equivalent in Spring? The <code>@Lock</code> customization feature is not necessary, I'm just looking for a better alternative than manually synchronizing every method of every Singleton Session Bean.</p>