efficient null evaluation in java
<p>i got the following method </p>

<pre><code>public Person findByAdd(String add) {
    try {
        final String queryString = "select p from Destinations p where p.address = :add";
        Query query = em.createQuery(queryString);
        query.setParameter("add", add);
        return (Person) query.getSingleResult();

    } catch (RuntimeException re) {
        throw re;
    }
}
</code></pre>

<p>which throws null-pointer exception if Person object does not exist,and i want to do something like this</p>

<pre><code>if(person.getAdd !=null){
   system.out.println ("address exist");    
}
else
{
system.out.println ("please enter address ");   
}
</code></pre>

<p>but this throws an exception if person doesn't exist,how can i efficiently evaluate the if person is null</p>
