How can I validate a copy constructor's parameter?

public class Rectangle {

  int width, height;

  public Rectangle(int width, int height) {
    this.width = width;
    this.height = height;
  }

  public Rectangle(Rectangle source) {
    this(source.width, source.height);
  } 
}

Let's say I have a class with multiple constructors, one of which is a copy-constructor (to copy an object).

Is there any way I can make check if source is null in the copy-constructor and throw an IllegalArgumentException if it is? Because the other constructor call has to be the first statement in my constructor.