Java quicksort: variable expected

package com.company;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;

public class Quicksort {

    public static int partition(ArrayList<Integer> sequence, int g, int d){

        int pivot = sequence.get(d);
        int i = g-1;

        for (int j = g; j<d; j++){

            if (sequence.get(j)<=pivot){
                i++;

                int temp = sequence.get(i);
                sequence.get(i) = sequence.get(j);
                sequence.get(j) = temp;
            }
        }

        int temp = sequence.get(i+1);
        sequence.get(i+1) = sequence.get(d);
        sequence.get(d) = temp;

        return i+1;

    }


    public static ArrayList quicksort(ArrayList<Integer> sequence, int g, int d){

        if (g<d){
            int part = partition(sequence, g, d);

            quicksort(sequence, g, part-1);
            quicksort(sequence, part+1, d);
        }

    return sequence;


//        ArrayList<Integer> flag = new ArrayList();
//
//        int pivot = sequence.size()/2;
//        int g = 0, d = sequence.size()-1;
//
//        System.out.println("le pivot est à l'index " + pivot);
//        System.out.println("d est à l'index "+d);
//
//
//        if (sequence.get(g)>sequence.get(pivot)){
//            sequence.add(pivot+1,sequence.get(g));
//            sequence.remove(g);
//        }
//
//        if(sequence.get(d)<sequence.get(pivot)){
//            sequence.add(pivot-1, sequence.get(d));
//
//        }
//
//        return sequence;


    }


    /**
     * test quicksort
     */
    public static void main(String[] args) {

        ArrayList sample3 = new ArrayList();
        sample3 = Sequence.sequenceGenerated(5);
        System.out.println("la liste générée est: " + sample3);
        sample3 = Quicksort.quicksort(sample3, 1, sample3.size()-1);
        System.out.println("quicksort: " + sample3 );


    }

}