title: How to replace "!= null" statement with method reference?
body: <p>My Intelij shows me that I can replace the lambda <code>.filter(bean -&gt; bean != null)</code> with a method reference. Its is obviuos for me how to do it when I have a Class or an Object with methods. But how to do a reference on <code>!= null</code>, is there a Class that has some kind of <code>isNull()</code> method?</p>