Yet another question on code optimization

Question

Hello again
Sorry for asking too many questions, but I really want to learn how to simplify my work.
Let's say I have this ArrayList that gets initialized every time a user clicks on a new combobox item and a set of numbers are added to it. I then add this arrayList to another arraylist that is initialized outside of the actionlistener class.
So basically every time the user clicks the inner arraylist is added to outer arraylist. But I don't want to have duplicate results if the user chooses to go back to the previous JTextAreas and delete the contents to start typing new stuff. The way i am doing this is like this:
ArrayList<String> filler = new ArrayList<String>(); //The filler that has to be unique, so the user won't screw with the pattern
filler.add("A*?1qkQOz]4X1QedyhA`H-6$U[I{]0n<RT.W})(J+z7o.<q[g5[y0YA2tv+c@WN");
//For each JtextArea object add a filler so that no Nullpointerexception happens with the use of arraylist.set()method....
for (int i = 0; i <textAreaObjs.size(); i ++){
     allValues.add(filler);
//Replace the unique filler with the actual user input saved in innerList which is of type ArrayList.               
allValues.set(textCounter,innerList);
//Remove all the unnecessary fillers
for (int outerArrayCounter = 0; outerArrayCounter < allValues.size(); outerArrayCounter ++){
     for (int innerArrayCounter = 0; innerArrayCounter < allValues.get(outerArrayCounter).size(); j++){
          if (allValues.get(outerArrayCounter).get(innerArrayCounter).equals("A*?1qkQOz]4X1QedyhA`H-6$U[I{]0n<RT.W})(J+z7o.<q[g5[y0YA2tv+c@WN")){
               allValues.remove(outerArrayCounter);
               outerArrayCounter--;
               break;
}I tried the different methods of the ArrayList like arraylist.set() and if there is a null at this location: do this, if not do something else but they returned Nullpointerexceptions...
I tried the isEmpty method too but that only checks to see if the whole list is empty and not specific parts of the array....
Is there a better, faster, and simpler way of doing this?
Thanks for the help.

Answer 1

I thought this might help... an example of a Sorted[Descending]Map of Lists... I didn't tackle the "frequency aspect" I just generated a random "key" for the map... and a random string to stuff in the Word...
I presume your Word is {String word, int lineNumber, int startIndex} from the source-document... and now you need to query your frequency table for "the most common word" or maybe "the top five words".
You can fill in the blanks.
... and BTW... If I where doing this for real I'd be awfully tempted to extend TreeMap into a "generic" DescendingTreeMap, which I would stick somewhere in my common utils package, from whence it could be reused in future by myself and others.
If you want the code for krc.utilz.RandomString just ask.
package forums;
import java.util.Collections;
import java.util.Collection;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.util.Comparator;
import java.util.Random;
import krc.utilz.RandomString;
public class SortedDescendingMap
  private static final RandomString RANDOM_STRING = new RandomString();
  private static final Random RANDOM = new Random();
  private class DescendingIntegerComparator implements Comparator<Integer>
    @Override
    public int compare(Integer a, Integer b) {
      return -1 * a.compareTo(b);
    @Override
    public boolean equals(Object o) {
      return this == o; // yes I do mean reference-equals.
  private class Word
    private final String word;
    public Word() {
      this.word = RANDOM_STRING.nextString(5);
    @Override
    public String toString() {
      return this.word;
  private final SortedMap <Integer,List<Word>> freqTable;
  private SortedDescendingMap() {
    freqTable = new TreeMap<Integer,List<Word>>(new DescendingIntegerComparator());
  private void populate() {
    for (int i=0; i<50; i++) {
      List<Word> list = new ArrayList<Word>();
      for (int j=1; j<=5; j++) {
        list.add(new Word());
      freqTable.put(RANDOM.nextInt(5), list);
  private void print() {
    for ( Map.Entry<Integer,List<Word>> entry : freqTable.entrySet() ) {
      System.out.println(entry.getKey()+": "+entry.getValue());
  public static void main(String[] args) {
    try {
      SortedDescendingMap map = new SortedDescendingMap();
      map.populate();
      map.print();
    } catch (Exception e) {
      e.printStackTrace();
}This doesn't mean that I like you, and you're still a Putz! ;-)
Cheers. Keith.