Here you can find the source of map(M map, K key, V value)
public static <K, V, M extends Map<K, V>> M map(M map, K key, V value)
//package com.java2s; /*/*from w w w . jav a 2 s . c o m*/ * Copyright (C) 2012 eXo Platform SAS. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ import java.util.HashMap; import java.util.Map; public class Main { public static <K, V, M extends Map<K, V>> M map(M map, K key, V value) { map.put(key, value); return map; } public static <K, V> HashMap<K, V> map(K key, V value) { HashMap<K, V> map = new HashMap<K, V>(); map.put(key, value); return map; } }