Here you can find the source of hashSet()
public static <T> Set<T> hashSet()
//package com.java2s; /*//from www . ja v a2 s . c o m * iteraplan is an IT Governance web application developed by iteratec, GmbH * Copyright (C) 2004 - 2014 iteratec, GmbH * * This program is free software; you can redistribute it and/or modify it under * the terms of the GNU Affero General Public License version 3 as published by * the Free Software Foundation with the addition of the following permission * added to Section 15 as permitted in Section 7(a): FOR ANY PART OF THE COVERED * WORK IN WHICH THE COPYRIGHT IS OWNED BY ITERATEC, ITERATEC DISCLAIMS THE * WARRANTY OF NON INFRINGEMENT OF THIRD PARTY RIGHTS. * * This program 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. See the GNU General Public License for more * details. * * You should have received a copy of the GNU Affero General Public License * along with this program; if not, see http://www.gnu.org/licenses or write to * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, * MA 02110-1301 USA. * * You can contact iteratec GmbH headquarters at Inselkammerstr. 4 * 82008 Munich - Unterhaching, Germany, or at email address info@iteratec.de. * * The interactive user interfaces in modified source and object code versions * of this program must display Appropriate Legal Notices, as required under * Section 5 of the GNU Affero General Public License version 3. * * In accordance with Section 7(b) of the GNU Affero General Public License * version 3, these Appropriate Legal Notices must retain the display of the * "iteraplan" logo. If the display of the logo is not reasonably * feasible for technical reasons, the Appropriate Legal Notices must display * the words "Powered by iteraplan". */ import java.util.Arrays; import java.util.HashSet; import java.util.Set; public class Main { /** * Creates an empty {@code HashSet} instance. * <p> * <b>Note:</b> If {@code E} is an {@link Enum} type, use {@link java.util.EnumSet#noneOf} * instead. * <p> * <b>Note:</b> If you need an <i>immutable</i> empty List, use * {@link java.util.Collections#emptySet}. * * @return A newly-created, initially-empty {@code HashSet}. */ public static <T> Set<T> hashSet() { return new HashSet<T>(); } /** * Creates a {@code HashSet} instance containing the given elements. * * @param ts The elements that the set should contain. * @return A newly-created {@code HashSet} containing the given elements (minus duplicates). */ public static <T> Set<T> hashSet(T... ts) { return new HashSet<T>(Arrays.asList(ts)); } }