Here you can find the source of printMap(Map extends K, ? extends V> theMap)
public static <K, V> String printMap(Map<? extends K, ? extends V> theMap)
//package com.java2s; /*// w w w. j a v a 2s. co m * Copyright (C) 2003-2011 eXo Platform SAS. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * 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 Affero 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/>. */ import java.util.Map; public class Main { public static <K, V> String printMap(Map<? extends K, ? extends V> theMap) { StringBuilder theBuf = new StringBuilder(); for (Map.Entry<? extends K, ? extends V> entry : theMap.entrySet()) { theBuf.append(entry.getKey()); theBuf.append(" --> "); theBuf.append(entry.getValue()); theBuf.append(System.getProperty("line.separator")); } return theBuf.toString(); } }