Here you can find the source of compareLists(final List list1, final List list2)
public static <T extends Comparable<? super T>> int compareLists(final List<? extends T> list1, final List<? extends T> list2)
//package com.java2s; /*//from w ww . ja v a 2s . c o m ======================================================================== SchemaCrawler http://www.schemacrawler.com Copyright (c) 2000-2016, Sualeh Fatehi <sualeh@hotmail.com>. All rights reserved. ------------------------------------------------------------------------ SchemaCrawler is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. SchemaCrawler and the accompanying materials are made available under the terms of the Eclipse Public License v1.0, GNU General Public License v3 or GNU Lesser General Public License v3. You may elect to redistribute this code under any of these licenses. The Eclipse Public License is available at: http://www.eclipse.org/legal/epl-v10.html The GNU General Public License v3 and the GNU Lesser General Public License v3 are available at: http://www.gnu.org/licenses/ ======================================================================== */ import java.util.Iterator; import java.util.List; public class Main { public static <T extends Comparable<? super T>> int compareLists(final List<? extends T> list1, final List<? extends T> list2) { if (list1 == null) { return -1; } if (list2 == null) { return 1; } int comparison = list1.size() - list2.size(); if (comparison == 0) { final Iterator<? extends T> iter1 = list1.iterator(); final Iterator<? extends T> iter2 = list2.iterator(); while (comparison == 0 && iter1.hasNext() && iter2.hasNext()) { final T object1 = iter1.next(); final T object2 = iter2.next(); comparison = object1.compareTo(object2); } } return comparison; } }