Here you can find the source of asSet(T... values)
@SafeVarargs public static <T> Set<T> asSet(T... values)
//package com.java2s; /*//ww w .j av a 2s. c o m * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.HashSet; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Set; public class Main { @SafeVarargs public static <T> Set<T> asSet(T... values) { return new HashSet<>(asList(values)); } @SafeVarargs public static <T> List<T> asList(T... values) { return isEmpty(values) ? Collections.emptyList() : Arrays.asList(values); } public static boolean isEmpty(CharSequence cs) { return length(cs) <= 0; } public static boolean isEmpty(Collection<?> c) { return (c == null) || c.isEmpty(); } public static boolean isEmpty(Map<?, ?> m) { return (m == null) || m.isEmpty(); } public static <T> boolean isEmpty(Iterable<? extends T> iter) { if (iter == null) { return true; } else if (iter instanceof Collection<?>) { return isEmpty((Collection<?>) iter); } else { return isEmpty(iter.iterator()); } } public static <T> boolean isEmpty(Iterator<? extends T> iter) { return iter == null || !iter.hasNext(); } @SafeVarargs public static <T> boolean isEmpty(T... a) { return length(a) <= 0; } public static boolean isEmpty(char[] chars) { return length(chars) <= 0; } public static int length(CharSequence cs) { return cs == null ? 0 : cs.length(); } @SafeVarargs public static <T> int length(T... a) { return a == null ? 0 : a.length; } public static int length(char[] chars) { return (chars == null) ? 0 : chars.length; } }