Java Perfect Number Exercise

package perfectnumbers;

import java.util.ArrayList;
import java.util.Objects;

final class PerfectNumber {

    private final Integer number;
    private Integer factor_sum;
    private final ArrayList<Integer> factors;

    public PerfectNumber(Integer number) {
        this.number = number;
        this.factors = new ArrayList<>();
    }

    public void factor() {
        this.factors.clear();
        this.factor_sum = 0;
        //
        for (int i = 1; i < this.number; i++) {
            if (((this.number % i)) == 0) {
                this.factors.add(i);
                this.factor_sum += i;
            }
        }
    }

    public Boolean isPerfect() {
        return Objects.equals(this.getNumber(), this.getFactor_sum());
    }

    public Integer getNumber() {
        return this.number;
    }

    public Integer getFactor_sum() {
        return this.factor_sum;
    }

    public Object[] getFactors() {
        return this.factors.toArray();
    }

    @Override
    public String toString() {
        return this.getNumber().toString();
    }

    public void display_perfect() {
        System.out.println(
                "The number "
                + this
                + (this.isPerfect() ? " is" : " isn't")
                + " a perfect number."
        );
        System.out.flush();
    }

    public void display_factors() {
        System.out.print("The number " + this + " has the factors ");
        display(this.getFactors());
        System.out.println(", summing to " + this.getFactor_sum() + ".");
        System.out.flush();
    }

    public static void display(final Object... values) {
        switch (values.length) {
            case 0: {
                System.out.print("<None>");
                break;
            }
            case 1: {
                System.out.print(values[0]);
                break;
            }
            case 2: {
                System.out.print(values[0] + " and " + values[1]);
                break;
            }
            default: {
                for (int i = 0; i < values.length - 1; i++) {
                    System.out.print(i + ", ");
                }
                System.out.print("and " + values[values.length - 1]);
            }
        }
        System.out.flush();
    }
}

/**
 *
 * @author Aidan
 */
public class PerfectNumbers {

    private static final int LOOPS = 10000;

    public static void main(String[] args) {
        ArrayList<PerfectNumber> tmp = new ArrayList<>();
        tmp.ensureCapacity(LOOPS);

        for (int i = 0; i < LOOPS; i++) {
            tmp.add(new PerfectNumber(i));
        }

        System.out.print("We have the numbers 1 through " + LOOPS + " inclusive.\n");
        System.out.flush();

        for (int i = 0; i < LOOPS; i++) {
            tmp.get(i).factor();
        }

        System.out.println();
        System.out.flush();

        for (int i = 0; i < LOOPS; i++) {
            if (tmp.get(i).isPerfect()) {
                tmp.get(i).display_factors();
            }
        }

        System.out.println();
        System.out.flush();

        for (int i = 0; i < LOOPS; i++) {
            if (tmp.get(i).isPerfect()) {
                tmp.get(i).display_perfect();
            }
        }

        System.out.println();
        System.out.flush();
    }

}