Controlling threads in Java

I have written threaded applications that spawn threads to do specific bulk processing and I have written apps that spawn a thread to function as a daemon (e.g. watching a directory for a file). I have started these java daemons by a servlet that gets loaded on startup, but I found this was not the best way. If the context shuts down then the threads are left without a parent. This eats up Tomcat's memory every time I undeploy/deploy the app. A better way is to have a context listener that starts up the threads and keeps a handle to the thread object. When the context shuts down you can use the handle to shutdown the threads properly. To counter this I need to find some way to control the execution of the thread. Most daemon type processes use code similar to this:

// Sets up an infinite loop .
while (true)
{
     // do the thread processing here.

}

I will alter this to be a Boolean value that I can change using some set methods in the object. This will provide me an interface for turning the thread on and off. Below is a partial listing of the class I end up with.

public class FileEvictor
{

private Boolean threadOn = true;
private int start = 1;
private  int stop = 2;

private void init()
{ 
   try
   {
       //Create background thread, which will be responsible for purging expired items.
       Thread threadCleanerUpper = new Thread( new Runnable()
       {

           public void run()
           {

               System.out.println("File Evictor Service is running.");

               try
               {
                   // Sets up an infinite loop .
                   while (threadOn)
                   {
                          // do the thread processing here.

                   }
               }
               catch (Exception e)
               {
                   System.out.println("Unknown exception" + e.getMessage());
                   e.printStackTrace();   
               }          
               finally
               {
                   //TODO more info on what bombed
               }         
               return;
           }
       }, "File Evictor"); // End class definition and close new thread definition

       // Sets the thread's priority to the minimum value.
       threadFileEvictor.setPriority( Thread.MIN_PRIORITY );

       // Starts the thread.
       threadFileEvictor.start();
   }

public FileEvictor(  int aStartHour, int aStopHour)
{
   start = aStartHour;
   stop = aStopHour;
   init();

}
public void setThreadOn()
{
   threadOn = true;
}
public void setThreadOff()
{
   threadOn = false;  
}

Once I have these start and stop methods in my thread, then all I have to do is create a context listener that will start the thread and stop the thread when the context comes up or down.