Here you can find the source of getStream(InputStream is)
public static ZipInputStream getStream(InputStream is)
//package com.java2s; /* $RCSfile$/*from ww w .j av a 2 s . com*/ * $Author$ * $Date$ * $Revision$ * * Copyright (C) 2006 The Jmol Development Team * * Contact: jmol-developers@lists.sf.net * * 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., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301, USA. */ import java.io.BufferedInputStream; import java.io.InputStream; import java.util.zip.ZipInputStream; public class Main { public static ZipInputStream getStream(InputStream is) { return (is instanceof ZipInputStream ? (ZipInputStream) is : is instanceof BufferedInputStream ? new ZipInputStream(is) : new ZipInputStream(new BufferedInputStream(is))); } }