title: Java null arguments when chaining Constructors
body: <p>Let's say I have a class with multiple constructors, one of which is a copy-constructor (to copy an object):</p>
  
  <pre><code>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);
      }
  }
  </code></pre>
  
  <p>Is there any way I can make check if <code>source</code> is <code>null</code> in the copy-constructor and throw an <code>IllegalArgumentException</code> if it is? Because the other constructor call <strong>has</strong> to be the first statement in my constructor.</p>