Java multithreading – passing data structures to threads

The application I'm writing generates a characterlist character at some stage At this stage, I am trying to create a thread to process the ArrayList The problem is how to pass this ArrayList to the thread

Description code:

class thisApp {
    /* Some initial processing creates an ArrayList - aList */

    Runnable proExec = new ProcessList (); //ProcessList implements Runnable
    Thread th = new Thread(proExec);
}

Descriptive code of processlist:

public class ProcessList implements Runnable {
    public void run() {
      /* Access the ArrayList - aList - and do something upon */
    }
}

My question is: how do I pass and access a list in run()?

Solution

You can simply pass an alist to the constructor of processlist, which can keep the reference until it is needed:

class thisApp {
    /* Some initial processing creates an ArrayList - aList */

    Runnable proExec = new ProcessList (aList);
    Thread th = new Thread(proExec);
}

public class ProcessList implements Runnable {
    private final ArrayList<Character> aList;
    public ProcessList(ArrayList<Character> aList) {
      this.aList = aList;
    }
    public void run() {
      /* use this.aList */
    }
}

Note: if multiple threads access the list at the same time and one or more threads modify it, all related code needs to be synchronized