Here you can find the source of toHashSet(Set
public static <T> Set<T> toHashSet(Set<T> inp)
//package com.java2s; /**/*from ww w . ja v a 2s . c om*/ * Copyright 2012-2015 Rafal Lewczuk <rafal.lewczuk@jitlogic.com> * <p/> * This is free software. You can redistribute it and/or modify it under the * terms of the GNU General Public License as published by the Free Software * Foundation, either version 3 of the License, or (at your option) any later * version. * <p/> * This software 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. * <p/> * You should have received a copy of the GNU General Public License * along with this software. If not, see <http://www.gnu.org/licenses/>. */ import java.util.*; public class Main { public static <T> Set<T> toHashSet(Set<T> inp) { Set<T> rslt = new HashSet<>(); rslt.addAll(inp); return rslt; } }