Sort ArrayList of objects by id

Question

I have ArrayList of containing 'MonthlySale' objects, below is my class.
import java.io.Serializable;
import java.util.ArrayList;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import org.hibernate.annotations.GenericGenerator;
@Entity
@Table(name="Month")
public class MonthlySale extends AuraDB implements Serializable, Comparable {
    private String quantity;
    private String value;
    private String avUnit;
    private int saleNumber;
    private int id;
    private String month;
    private String saleYear;
    private String description;
    private int reportNumber;
    public MonthlySale() {
    public MonthlySale(int saleNumber, String saleYear) {
        this.saleNumber = saleNumber;
        this.saleYear = saleYear;
    public MonthlySale(int saleNumber, String saleYear, int reportNumber) {
        this.saleNumber = saleNumber;
        this.saleYear = saleYear;
        this.reportNumber = reportNumber;
    @Column(name="AV_UNIT")
    public String getAvUnit() {
        return avUnit;
    public void setAvUnit(String avUnit) {
        this.avUnit = avUnit;
    @Column(name="MONTH")
    public String getMonth() {
        return month;
    public void setMonth(String month) {
        this.month = month;
    @Column(name="QUANTITY")
    public String getQuantity() {
        return quantity;
    public void setQuantity(String quantity) {
        this.quantity = quantity;
    @Column(name="SALES_NO")
    public int getSaleNumber() {
        return saleNumber;
    public void setSaleNumber(int saleNumber) {
        this.saleNumber = saleNumber;
    @Column(name="SALES_YEAR")
    public String getSaleYear() {
        return saleYear;
    public void setSaleYear(String saleYear) {
        this.saleYear = saleYear;
    @Column(name="VALUE")
    public String getValue() {
        return value;
    public void setValue(String value) {
        this.value = value;
    @Id
    @GenericGenerator(name="generator", strategy="increment")
    @GeneratedValue(generator="generator")
    @Column(name="ID")
    public int getId() {
        return id;
    public void setId(int id) {
        this.id = id;
    @Column(name="DESCRIPTION")
    public String getDescription() {
        return description;
    public void setDescription(String description) {
        this.description = description;
    @Column(name="REPORT_ID")
    public int getReportNumber() {
        return reportNumber;
    public void setReportNumber(int reportNumber) {
        this.reportNumber = reportNumber;
     public void selectMonthList() {
        hibSelectAll(this, "SELECT DISTINCT month FROM MonthlySale WHERE sales_year='" + saleYear + "' AND " +
                " sales_no = '" + saleNumber + "'");
}I want my arraylist to be ordered by id. I used collection.sort(), but i cannot sort by id.
I get objects arrayList like this way
            monthlySale = new MonthlySale(Integer.parseInt(sales_no), sales_year, 0);
            monthlySale.selectMonthList();Any help appreciated.
regards,
Dil.

Answer 1

Of course yes i did, like this.
public int compareTo(Object o) {
       if(this.id == ((MonthlySale)o).getId()){
            return 0;
       }else if(this.id > ((MonthlySale)o).getId()){
            return 1;
       }else{
            return -1;
    }I implement 'MonthlySale class' form Comparable interface and override above method but it doesn't work.