Exception is occurred while trying to compare dates - Nullpointerexception and also get method is returning null value even if i have set the date

NUllpointerexception is occured while trying to compare dates.
I noticed that while debugging that expectedDate and arrivedDate variable value is getting current date time where as i am using set Method to set date.Please correct my code for comparing dates. My method is used to find whether the shipment will arrive on time or before expected or after expected.

public class ShipmentBO {

    public void displayStatusOfShipment(Shipment shipment) {

        Date expectedDate = new Date();
        Date arrivedDate = new Date();
        SimpleDateFormat df = new SimpleDateFormat("dd-MM-yyyy");

        Shipment s = new Shipment();
        ShipmentStatus SStatus = new ShipmentStatus();
        expectedDate = s.getexpectedDeliveryDate();
        arrivedDate = SStatus.getarrivedDate();

        String s1 = df.format(expectedDate);
        String s2 = df.format(arrivedDate);

        if (expectedDate.after(arrivedDate)) {
            System.out.println("The shipment arrived after the expected date");
        } else
        if (expectedDate.before(arrivedDate)) {
            System.out.println("The shipment arrived before the expected date");
        }
    }

I am setting the date in the below main class

 public static void main(String[] args) throws ParseException {
		
	 Scanner sc = new Scanner(System.in);
	 System.out.println("Enter the shipment details :");
	 String userDetail = sc.nextLine();
	 String userDetailParts[] = userDetail.split(",");
      //System.out.println(Arrays.toString(userDetailParts));
        
     Shipment shipment = new Shipment();
     SimpleDateFormat sdf = new SimpleDateFormat("dd-MM-yyyy"); 
     shipment.setid(userDetailParts[0]); 
     shipment.setsourcePort(userDetailParts[1]); 
     shipment.setdestinationPort(userDetailParts[2]);
     shipment.setexpectedDeliveryDate(sdf.parse(userDetailParts[3])); 
     shipment.setcustomerName(userDetailParts[4]);
}

And the input I am giving as a comma separated - STAJU01, Hong Kong, Cochin,20-05-2017, karthick

Shipment class:

import java.util.Date;

public class Shipment {
	private String id;
	private String sourcePort;
	private String destinationPort;
	private Date expectedDeliveryDate;
	private String customerName;
	private ShipmentStatus[] shipmentStatus;

	public String getid() {
		return id;
	}

	public void setid(String id) {
		this.id = id;
	}

	public String getsourcePort() {
		return sourcePort;
	}

	public void setsourcePort(String sourcePort) {
		this.sourcePort = sourcePort;
	}

	public String getdestinationPort() {
		return destinationPort;
	}

	public void setdestinationPort(String destinationPort) {
		this.destinationPort = destinationPort;
	}

	public Date getexpectedDeliveryDate() {
		return expectedDeliveryDate;
	}

	public void setexpectedDeliveryDate(Date expectedDeliveryDate) {
		this.expectedDeliveryDate = expectedDeliveryDate;
	}

	public String getcustomerName() {
		return customerName;
	}

	public void setcustomerName(String customerName) {
		this.customerName = customerName;
	}

	public Shipment() {
	}

	public Shipment(String id, String sourcePort, String destinationPort, Date expectedDeliveryDate,
			String customerName) {
		this.id = id;
		this.sourcePort = sourcePort;
		this.destinationPort = destinationPort;
		this.expectedDeliveryDate = expectedDeliveryDate;
		this.customerName = customerName;
	}

	public ShipmentStatus[] getShipmentStatus() {
		return shipmentStatus;
	}

	public void setShipmentStatus(ShipmentStatus[] shipmentStatus) {
		this.shipmentStatus = shipmentStatus;
	}
}

ShipmentStatus:

import java.util.Date;

public class ShipmentStatus {
	private String arrivalPort;
	private String departurePort;
	private Date arrivedDate;
	private String status;
	private Shipment shipment;

	public Shipment getshipment() {
		return shipment;
	}

	public void setshipment(Shipment shipment) {
		this.shipment = shipment;
	}

	public String getarrivalPort() {
		return arrivalPort;
	}

	public void setarrivalPort(String arrivalPort) {
		this.arrivalPort = arrivalPort;
	}

	public String getdeparturePort() {
		return departurePort;
	}

	public void setdeparturePort(String departurePort) {
		this.departurePort = departurePort;
	}

	public Date getarrivedDate() {
		return arrivedDate;
	}

	public void setarrivedDate(Date arrivedDate) {
		this.arrivedDate = arrivedDate;
	}

	public String getstatus() {
		return status;
	}

	public void setstatus(String status) {
		this.status = status;
	}

	public ShipmentStatus() {
	}

	public ShipmentStatus(String arrivalPort, String departurePort, Date arrivedDate, String status,
			Shipment shipment) {
		this.arrivalPort = arrivalPort;
		this.departurePort = departurePort;
		this.arrivedDate = arrivedDate;
		this.status = status;
		this.shipment = shipment;
	}
}

You are calling the getexpectedDeliveryDate() on a new Shipment(), but I suspect you want to call it on the shipment you receive as a parameter, which you otherwise leave untouched. Basically, try changing expectedDate = s.getexpectedDeliveryDate(); to expectedDate = shipment.getexpectedDeliveryDate();

See comments in code:

public void displayStatusOfShipment(Shipment shipment) {

    // not used:
	// SimpleDateFormat df = new SimpleDateFormat("dd-MM-yyyy");

    // extract date from passed shipment instance
	Date expectedDate = shipment.getexpectedDeliveryDate();
	// I assume ShipmentStatus is part of Shipment so you don't need a new instance here
    // ShipmentStatus SStatus = new ShipmentStatus();
    // extract arrivalDate from passed shipment's ShipmentStatus:
	Date arrivedDate = shipment.getShipmentStatus().getarrivedDate();

	// not used :
	// String s1 = df.format(expectedDate);
	// String s2 = df.format(arrivedDate);

	if (expectedDate.after(arrivedDate)) {
		System.out.println("The shipment arrived after the expected date");
	} else
	if (expectedDate.before(arrivedDate)) {
		System.out.println("The shipment arrived before the expected date");
	}
}

In Shipment add a method which contains the logic to obtain the arrivedDate of the shipment using the ShipmentStatus array. You say it's the third last ShipmentStatus so the code can be:

class Shipment {
    public Date getArrivedDate() {
       if(shipmentStatus!=null && shipmentStatus.length>=3)
           return shipmentStatus[shipmentStatus.length-3].getArrivedDate();
       return null;
    }
}

I'm not sure if the 3rd last status is a good way to identify the right shipment status. It think it would be better to make your choice based on some business logic. For example:

* first shipment status with arrivedDate!=null
* last shipment status with arrivedDate!=null
* shipmentStatus with status='arrival'

> get method is returning null value even if i have set the date

It's because you are not using the Shipment object passed to displayStatusOfShipment(Shipment shipment); rather, you are creating a new instance as follows:

Date expectedDate = new Date();
Shipment s=new Shipment();
expectedDate = s.getexpectedDeliveryDate();

You should replace all the above three lines with the following line:

Date expectedDate = shipment.getexpectedDeliveryDate();

Similarly, to this method, you should pass a parameter of the type, ShipmentStatus for the arrival date and use the same to get the arrival date i.e. you need to replace the following three lines in the similar way as shown above:

Date arrivedDate = new Date();
ShipmentStatus SStatus = new ShipmentStatus();
arrivedDate = SStatus.getarrivedDate();

On comparing dates:

I had suggested you to stop using the poorly designed java.util.Date and to switch to the modern java.time API. This scenario is a perfect example for you to make that switch immediately. Let's see why:

1. The modern date-time API has a class called, LocalDate which represents just date i.e. it has just three fields: year, month and day and therefore when you compare two instances of LocalDate, only these fields are compared. LocalDate has a rich set of API for comparison e.g. LocalDate#isAfter, LocalDate#isBefore, LocalDate#isEqual etc. which compare the values of these three fields to give you the result.

2. You will say that java.util.Date also has Date#before, Date#after etc. but this is where the comparison of these methods with those of the LocalDate ends. These methods of java.util.Date compare the milliseconds since January 1, 1970, 00:00:00 GMT i.e. one instance of Date can be before/after even with a difference of a millisecond (unlike two instances of LocalDate which can be before/after only with the difference in one or more of the fields, day, month, and year).

   public class Main {
       public static void main(String[] args) {
           Date date1 = new Date();
           Date date2 = new Date();
           date2.setTime(date1.getTime() - 1);
           System.out.println(date1);
           System.out.println(date2);
           System.out.println(date1.after(date2));
       }
   }
   

   Output:

   Wed Aug 19 16:34:56 BST 2020
   Wed Aug 19 16:34:56 BST 2020
   true
   

If you still insist to use java.util.Date:

If you still insist to use java.util.Date, you will have to get the day, month and year from the two instances of Date yourself and compare them to determine before/after cases. The choice is yours.