Java tutorial
//package com.java2s; import java.util.Collections; import java.util.Map; import javax.annotation.Nullable; public class Main { /** * Returns an non null value based on the giving {@link Map} * * @param map * value to evaluate * @return the original value or an empty {@link Map} * @since 4.2 */ public static <K, V> Map<K, V> nonNullMap(@Nullable final Map<K, V> map) { return map == null ? Collections.emptyMap() : map; } }