Java tutorial
//package com.java2s; //License from project: Open Source License import java.util.Collection; public class Main { public static void checkCollectionDoesNotContainNull(final Collection<?> collection) { boolean containsNull = false; try { containsNull = collection.contains(null); } catch (NullPointerException ex) { // Not a problem. } if (containsNull) { throw new NullPointerException(); } } }