Here you can find the source of getFileExtension(final File file)
public static String getFileExtension(final File file)
//package com.java2s; /*/*from w w w. ja v a2 s . c om*/ * * SchemaCrawler * http://sourceforge.net/projects/schemacrawler * Copyright (c) 2000-2013, Sualeh Fatehi. * * This library 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 library 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 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307, USA. * */ import java.io.File; public class Main { public static String getFileExtension(final File file) { final String ext; if (file != null) { final String scriptFileName = file.getName(); ext = scriptFileName.lastIndexOf('.') == -1 ? "" : scriptFileName.substring(scriptFileName.lastIndexOf('.') + 1, scriptFileName.length()); } else { ext = ""; } return ext; } }