Here you can find the source of isBlank(final Collection
public static final <T> boolean isBlank(final Collection<T> collection)
//package com.java2s; //License from project: Open Source License import java.util.Collection; public class Main { public static final <T> boolean isBlank(final Collection<T> collection) { return (collection == null) || isEmpty(collection); }// ww w . j a v a 2 s . com public static final <T> boolean isEmpty(final Collection<T> collection) { return (collection == null) || collection.isEmpty(); } }