L try to import class to this package but it wont compile

See more:

Java

l try to complies the code but there is an error and l did import to classes using both blue j and net bean compiler as bleo code

import java.text.DecimalFormat;
import java.util.Random;

public class AverageSpeedOfStructures
{
     public static void main(String args[])
     {
          //create a ArrayClass object
          ArrayClass array = new ArrayClass(1000000);
         
          //create a SingleLinkedList class object
          SingleLinkedList<Integer> sll = new SingleLinkedList<Integer>();
     
          //create a Random object
          Random rand = new Random();
        
          //create a DecimalFormat object
          DecimalFormat form = new DecimalFormat("##.####");
       
          //declare the required variables to calculate and store
          double totalofArray = 0;
          double totalofSLL = 0;
          long arrInsert, arrDelete, arrSearch;
          long sllInsert, sllDelete, sllSearch;
          long start, end;

          //logic to find the time taken by insert method
          start = System.nanoTime();
          for (int i = 0; i < 1000000; i++)
          {
              array.insert(rand.nextInt(1000));
          }
          end = System.nanoTime();
          arrInsert = Math.abs(start - end);
         
          //logic to find the time taken by search method
          start = System.nanoTime();
          array.search(300);
          end = System.nanoTime();
          arrSearch = Math.abs(start - end);
         
          //logic to find the time taken by delete method
          start = System.nanoTime();
          array.delete(300);
          end = System.nanoTime();
          arrDelete = Math.abs(start - end);
         
          //average time taken by the ArrayClass using arrays
          totalofArray = (arrInsert + arrDelete + arrSearch) / 3.0;

          // Single LinkedList speeds
          //logic to find the time taken by insert method
          start = System.nanoTime();
          for (int i = 0; i < 1000000; i++)
          {
              sll.listInsert(rand.nextInt(1000));
          }
          end = System.nanoTime();
          sllInsert = Math.abs(start - end);
         
          //logic to find the time taken by search method
          start = System.nanoTime();
          sll.listSearch(300);
          end = System.nanoTime();
          sllSearch = Math.abs(start - end);
         
          //logic to find the time taken by delete method
          start = System.nanoTime();
          sll.listRemove(300);
          end = System.nanoTime();
          sllDelete = Math.abs(start - end);

          //average time taken by the singly linked list
          totalofSLL = (sllInsert + sllDelete + sllSearch) / 3.0;
          //print the ratio of speeds
          System.out
                   .println("The ratio of averge speed of an Unsorted-Optimized"
                             + " array structure \nto the average speed of a"
                             + " Singly Linked List structure is: \n"
                             + form.format(totalofArray)
                             + " : "
                             + form.format(totalofSLL));
     }
}

why there is an error?

What I have tried:

l did try to import both classes form java but the code wont compile and where is the error ??