How can I make this class immutable?

[fatabass]

package myPackage;

import java.util.*;

public final class Student {

	private int						id;
	private String					name;
	private final java.util.Date	dateCreated;

	public Student(int ssn, String newName) {
		id = ssn;
		name = newName;
		dateCreated = new java.util.Date();
	}

	// end constructor

	public int getId() {
		return id;
	}

	// end getId

	public String getName() {
		return name;
	}

	// end getName

	public Date getDateCreated() {
		return dateCreated;
	}
	// end getDateCreated

}

package myPackage;

public class PrinterClass {
	
	public void printer(String text)
	{
		System.out.println(text);
	}
	
	public void printer(int text)
	{
		System.out.println(text);
	}
	
	public void printer(Object o)
	{
		System.out.println(o);
	}

}

package myPackage;

import java.util.Date;

public class Test {

	public static void main(String[] args) {
		
		Student student = new Student(123,"John");
		
		PrinterClass printer = new PrinterClass();
		
		printer.printer(student.getId());
		printer.printer(student.getName());
		printer.printer(student.getDateCreated());
		
		Date myDate = student.getDateCreated();
		myDate.setMonth(1);
		printer.printer(student.getDateCreated());
		
		
	}
}

I want to make my Student class immutable.

But as you can see I am able to play with the dateCreated field by:

Date myDate = student.getDateCreated();
myDate.setMonth(1);

Is there anyway to protect my dateCreated field?

[JosAH]

Return a copy of the Date object?

kind regards,

Jos

[fatabass]

Sorry ?

[JosAH]

Sorry ?

Instead of returning your dateCreated object, return a copy of it; so the caller/receiver can only modify that copy while the original object remains unaltered.

kind regards,

Jos

[fatabass]

Thanks.

If it is not too much trouble can you make an example with codes?

[Fubarable]

If it is not too much trouble can you make an example with codes?

Um,...it's one line of code for gosh's sake. Just try it. Calling clone() would do the trick.

[fatabass]

Thank you.