The lowest priority is ``Job.DECORATE``.

```scala
// extracted from the org.eclipse.core.runtime.jobs.Job class

 /** 
  * Job priority constant (value 30) for long-running background jobs.
  * 
  * @see #getPriority()
  * @see #setPriority(int)
  * @see #run(IProgressMonitor)
  */
  public static final int LONG = 30;

  /** 
   * Job priority constant (value 50) for decoration jobs.
   * Decoration jobs have lowest priority.  Decoration jobs generally
   * compute extra information that the user may be interested in seeing
   * but is generally not waiting for.
   * 
   * @see #getPriority()
   * @see #setPriority(int)
   * @see #run(IProgressMonitor)
   */
   public static final int DECORATE = 50;
```