code: public void writeStatement(Statement oldStat)
  	{
  		if (oldStat == null)
  		{
  			throw new NullPointerException();
  		}
  		Statement newStat = createNewStatement(oldStat);
  		try
  		{
  			// execute newStat
  			newStat.execute();
  		}
  		catch (Exception e)
  		{
  			listener.exceptionThrown(new Exception("failed to write statement: " + oldStat, e)); //$NON-NLS-1$
  		}
  	}
docs: Write a statement of old objects.
  <p>
  A new statement is created by using the new versions of the target and arguments. If any of the objects do not have its new copy yet,
  <code>writeObject()</code> is called to create one.
  </p>
  <p>
  The new statement is then executed to change the state of the new object.
  </p>
  
  @param oldStat
  a statement of old objects