Here you can find the source of of(E e1, E... e)
public static final <E extends Enum<E>> EnumSet<E> of(E e1, E... e)
//package com.java2s; /**/*from w w w. jav a2 s . c o m*/ * SqlJetUtility.java * Copyright (C) 2009-2010 TMate Software Ltd * * This program 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; version 2 of the License. * * 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. * * For information on how to redistribute this software under * the terms of a license other than GNU General Public License * contact TMate Software at support@sqljet.com */ import java.util.EnumSet; public class Main { public static final <E extends Enum<E>> EnumSet<E> of(E e1, E... e) { return EnumSet.of(e1, e); } public static final <E extends Enum<E>> EnumSet<E> of(E e) { return EnumSet.of(e); } public static final <E extends Enum<E>> EnumSet<E> of(E e1, E e2) { return EnumSet.of(e1, e2); } public static final <E extends Enum<E>> EnumSet<E> of(E e1, E e2, E e3) { return EnumSet.of(e1, e2, e3); } }