Static data in runnable objects of threadpool

Question

hi all,
I have a threadpool and schedule Runnable objects into it.
The runnble objects are run as per schedule.
But I want to declare and initialize a static data in the runnable object. And I expect it to be initialised only once ie, the first time the runnable object is invoked by the threadpool and to be ignored in the subsequent scheduled invocations. And I want to access the static data throught the runnable object.
I want to know whether the above behavior will take place or should i use any other ways to do this.

Answer 1

Then maybe something like this?
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Date;
public class RunnableWithPreviousState implements Runnable {
    private static class State {
     public Date startTime, endTime;
     public State() {
         startTime = new Date();
    private static List<RunnableWithPreviousState> runnables = Collections
         .synchronizedList(new ArrayList<RunnableWithPreviousState>());
    private State previousState, myState;
    @Override
    public void run() {
     myState = new State();
     runnables.add(this);
     int index = runnables.indexOf(this);
     if (index > 0) {
         index -= 1;
         previousState = runnables.get(index).myState;
     if (previousState != null) {
         // inspect previousState
     // do other processing
     myState.endTime = new Date();
}Piet