Generate all the combinations of words from character in a matrix using Java

WordMatrixCombinations.java

package com.derp;

import java.util.ArrayList;
import java.util.Collections;

public class Main {
  public static ArrayList<String> combineCharWithWords( String character,
                                                        ArrayList<String> words ) {
    ArrayList<String> result = new ArrayList<>();

    for ( String word : words ) {
      String prefixed = character + word;
      String suffixed = word + character;

      result.add( prefixed );
      result.add( suffixed );
    }

    return result;
  }

  public static void main( String[] args ) {
    String[][] matrix = { { "C", "A" }, { "T", "O" } };

    ArrayList<String> originalChars = new ArrayList<>();

    for ( int i = 0; i < matrix.length; i++ ) {
      for ( int j = 0; j < matrix[ 0 ].length; j++ ) {
        originalChars.add( matrix[ i ][ j ] );
      }
    }

    ArrayList<String> previousWords = new ArrayList<>();
    previousWords.addAll( originalChars );

    int numberRepeats = 4;

    for ( int i = 0; i < numberRepeats; i++ ) {
      System.out.println( "Iteration number " + i );

      ArrayList<String> subFindings = new ArrayList<>();

      for ( String currentChar : originalChars ) {
        ArrayList<String> subResult = Main.combineCharWithWords( currentChar, previousWords );

        for ( String currentWord : subResult ) {
          if ( !subFindings.contains( currentWord ) ) {
            subFindings.add( currentWord );
          }
        }
      }

      for ( String currentWord : subFindings ) {
        if ( !previousWords.contains( currentWord ) ) {
          previousWords.add( currentWord );
        }
      }
    }

    Collections.sort( previousWords );

    System.out.println( "Previous words" );
    System.out.println( previousWords );
  }
}