Here you can find the source of mkDir(File dir)
public static void mkDir(File dir) throws IOException
//package com.java2s; /******************************************************************************* * Copyright (c) OSMCB developers/* w w w . j av a 2s. c om*/ * * 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, either version 2 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 General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. ******************************************************************************/ import java.io.File; import java.io.IOException; public class Main { public static void mkDir(File dir) throws IOException { if (dir.isDirectory()) return; if (!dir.mkdir()) throw new IOException("Failed to create directory \"" + dir.getAbsolutePath() + "\""); } }