https://openjdk.java.net/ 
/*
 * Copyright (c) 1995, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.util.zip;

import java.io.Closeable;
import java.io.InputStream;
import java.io.IOException;
import java.io.EOFException;
import java.io.File;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.WeakHashMap;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;

import static java.util.zip.ZipConstants64.*;


This class is used to read entries from a zip file.

 Unless otherwise noted, passing a null argument to a constructor or method in this class will cause a NullPointerException to be thrown. 
Author:     David Connelly
/**
 * This class is used to read entries from a zip file.
 *
 * <p> Unless otherwise noted, passing a <tt>null</tt> argument to a constructor
 * or method in this class will cause a {@link NullPointerException} to be
 * thrown.
 *
 * @author      David Connelly
 */
public
class ZipFile implements ZipConstants, Closeable {
    private long jzfile;  // address of jzfile data
    private final String name;     // zip file name
    private final int total;       // total number of entries
    private final boolean locsig;  // if zip file starts with LOCSIG (usually true)
    private volatile boolean closeRequested = false;

    private static final int STORED = ZipEntry.STORED;
    private static final int DEFLATED = ZipEntry.DEFLATED;

    
Mode flag to open a zip file for reading.

/**
     * Mode flag to open a zip file for reading.
     */
    public static final int OPEN_READ = 0x1;

    
Mode flag to open a zip file and mark it for deletion.  The file will be
deleted some time between the moment that it is opened and the moment
that it is closed, but its contents will remain accessible via the
ZipFile object until either the close method is invoked or the
virtual machine exits.

/**
     * Mode flag to open a zip file and mark it for deletion.  The file will be
     * deleted some time between the moment that it is opened and the moment
     * that it is closed, but its contents will remain accessible via the
     * <tt>ZipFile</tt> object until either the close method is invoked or the
     * virtual machine exits.
     */
    public static final int OPEN_DELETE = 0x4;

    static {
        /* Zip library is loaded from System.initializeSystemClass */
        initIDs();
    }

    private static native void initIDs();

    private static final boolean usemmap;

    private static final boolean ensuretrailingslash;

    static {
        // A system prpperty to disable mmap use to avoid vm crash when
        // in-use zip file is accidently overwritten by others.
        String prop = sun.misc.VM.getSavedProperty("sun.zip.disableMemoryMapping");
        usemmap = (prop == null ||
                   !(prop.length() == 0 || prop.equalsIgnoreCase("true")));

        // see getEntry() for details
        prop = sun.misc.VM.getSavedProperty("jdk.util.zip.ensureTrailingSlash");
        ensuretrailingslash = prop == null || !prop.equalsIgnoreCase("false");
    }

    
Opens a zip file for reading.

First, if there is a security manager, its checkRead
method is called with the name argument as its argument
to ensure the read is allowed.

The UTF-8 charset is used to decode the entry names and comments. 
Params:
  • name – the name of the zip file
Throws:
  • ZipException – if a ZIP format error has occurred
  • IOException – if an I/O error has occurred
  • SecurityException – if a security manager exists and its
        checkRead method doesn't allow read access to the file.
See Also:
/**
     * Opens a zip file for reading.
     *
     * <p>First, if there is a security manager, its <code>checkRead</code>
     * method is called with the <code>name</code> argument as its argument
     * to ensure the read is allowed.
     *
     * <p>The UTF-8 {@link java.nio.charset.Charset charset} is used to
     * decode the entry names and comments.
     *
     * @param name the name of the zip file
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     * @throws SecurityException if a security manager exists and its
     *         <code>checkRead</code> method doesn't allow read access to the file.
     *
     * @see SecurityManager#checkRead(java.lang.String)
     */
    public ZipFile(String name) throws IOException {
        this(new File(name), OPEN_READ);
    }

    
Opens a new ZipFile to read from the specified
File object in the specified mode.  The mode argument
must be either OPEN_READ or OPEN_READ | OPEN_DELETE.

First, if there is a security manager, its checkRead
method is called with the name argument as its argument to
ensure the read is allowed.

The UTF-8 charset is used to decode the entry names and comments 
Params:
  • file – the ZIP file to be opened for reading
  • mode – the mode in which the file is to be opened
Throws:
  • ZipException – if a ZIP format error has occurred
  • IOException – if an I/O error has occurred
  • SecurityException – if a security manager exists and
        its checkRead method
        doesn't allow read access to the file,
        or its checkDelete method doesn't allow deleting
        the file when the OPEN_DELETE flag is set.
  • IllegalArgumentException – if the mode argument is invalid
See Also:
Since:1.3
/**
     * Opens a new <code>ZipFile</code> to read from the specified
     * <code>File</code> object in the specified mode.  The mode argument
     * must be either <tt>OPEN_READ</tt> or <tt>OPEN_READ | OPEN_DELETE</tt>.
     *
     * <p>First, if there is a security manager, its <code>checkRead</code>
     * method is called with the <code>name</code> argument as its argument to
     * ensure the read is allowed.
     *
     * <p>The UTF-8 {@link java.nio.charset.Charset charset} is used to
     * decode the entry names and comments
     *
     * @param file the ZIP file to be opened for reading
     * @param mode the mode in which the file is to be opened
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     * @throws SecurityException if a security manager exists and
     *         its <code>checkRead</code> method
     *         doesn't allow read access to the file,
     *         or its <code>checkDelete</code> method doesn't allow deleting
     *         the file when the <tt>OPEN_DELETE</tt> flag is set.
     * @throws IllegalArgumentException if the <tt>mode</tt> argument is invalid
     * @see SecurityManager#checkRead(java.lang.String)
     * @since 1.3
     */
    public ZipFile(File file, int mode) throws IOException {
        this(file, mode, StandardCharsets.UTF_8);
    }

    
Opens a ZIP file for reading given the specified File object.

The UTF-8 charset is used to decode the entry names and comments. 
Params:
  • file – the ZIP file to be opened for reading
Throws:
/**
     * Opens a ZIP file for reading given the specified File object.
     *
     * <p>The UTF-8 {@link java.nio.charset.Charset charset} is used to
     * decode the entry names and comments.
     *
     * @param file the ZIP file to be opened for reading
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     */
    public ZipFile(File file) throws ZipException, IOException {
        this(file, OPEN_READ);
    }

    private ZipCoder zc;

    
Opens a new ZipFile to read from the specified
File object in the specified mode.  The mode argument
must be either OPEN_READ or OPEN_READ | OPEN_DELETE.

First, if there is a security manager, its checkRead
method is called with the name argument as its argument to
ensure the read is allowed.

Params:
  • file – the ZIP file to be opened for reading
  • mode – the mode in which the file is to be opened
  • charset –  the charset to be used to decode the ZIP entry name and comment that are not encoded by using UTF-8 encoding (indicated by entry's general purpose flag).
Throws:
  • ZipException – if a ZIP format error has occurred
  • IOException – if an I/O error has occurred
  • SecurityException – 
        if a security manager exists and its checkRead
        method doesn't allow read access to the file,or its
        checkDelete method doesn't allow deleting the
        file when the OPEN_DELETE flag is set
  • IllegalArgumentException – if the mode argument is invalid
See Also:
Since:1.7
/**
     * Opens a new <code>ZipFile</code> to read from the specified
     * <code>File</code> object in the specified mode.  The mode argument
     * must be either <tt>OPEN_READ</tt> or <tt>OPEN_READ | OPEN_DELETE</tt>.
     *
     * <p>First, if there is a security manager, its <code>checkRead</code>
     * method is called with the <code>name</code> argument as its argument to
     * ensure the read is allowed.
     *
     * @param file the ZIP file to be opened for reading
     * @param mode the mode in which the file is to be opened
     * @param charset
     *        the {@linkplain java.nio.charset.Charset charset} to
     *        be used to decode the ZIP entry name and comment that are not
     *        encoded by using UTF-8 encoding (indicated by entry's general
     *        purpose flag).
     *
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     *
     * @throws SecurityException
     *         if a security manager exists and its <code>checkRead</code>
     *         method doesn't allow read access to the file,or its
     *         <code>checkDelete</code> method doesn't allow deleting the
     *         file when the <tt>OPEN_DELETE</tt> flag is set
     *
     * @throws IllegalArgumentException if the <tt>mode</tt> argument is invalid
     *
     * @see SecurityManager#checkRead(java.lang.String)
     *
     * @since 1.7
     */
    public ZipFile(File file, int mode, Charset charset) throws IOException
    {
        if (((mode & OPEN_READ) == 0) ||
            ((mode & ~(OPEN_READ | OPEN_DELETE)) != 0)) {
            throw new IllegalArgumentException("Illegal mode: 0x"+
                                               Integer.toHexString(mode));
        }
        String name = file.getPath();
        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            sm.checkRead(name);
            if ((mode & OPEN_DELETE) != 0) {
                sm.checkDelete(name);
            }
        }
        if (charset == null)
            throw new NullPointerException("charset is null");
        this.zc = ZipCoder.get(charset);
        long t0 = System.nanoTime();
        jzfile = open(name, mode, file.lastModified(), usemmap);
        sun.misc.PerfCounter.getZipFileOpenTime().addElapsedTimeFrom(t0);
        sun.misc.PerfCounter.getZipFileCount().increment();
        this.name = name;
        this.total = getTotal(jzfile);
        this.locsig = startsWithLOC(jzfile);
    }

    
Opens a zip file for reading.

First, if there is a security manager, its checkRead
method is called with the name argument as its argument
to ensure the read is allowed.

Params:
  • name – the name of the zip file
  • charset –  the charset to be used to decode the ZIP entry name and comment that are not encoded by using UTF-8 encoding (indicated by entry's general purpose flag).
Throws:
  • ZipException – if a ZIP format error has occurred
  • IOException – if an I/O error has occurred
  • SecurityException – 
        if a security manager exists and its checkRead
        method doesn't allow read access to the file
See Also:
Since:1.7
/**
     * Opens a zip file for reading.
     *
     * <p>First, if there is a security manager, its <code>checkRead</code>
     * method is called with the <code>name</code> argument as its argument
     * to ensure the read is allowed.
     *
     * @param name the name of the zip file
     * @param charset
     *        the {@linkplain java.nio.charset.Charset charset} to
     *        be used to decode the ZIP entry name and comment that are not
     *        encoded by using UTF-8 encoding (indicated by entry's general
     *        purpose flag).
     *
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     * @throws SecurityException
     *         if a security manager exists and its <code>checkRead</code>
     *         method doesn't allow read access to the file
     *
     * @see SecurityManager#checkRead(java.lang.String)
     *
     * @since 1.7
     */
    public ZipFile(String name, Charset charset) throws IOException
    {
        this(new File(name), OPEN_READ, charset);
    }

    
Opens a ZIP file for reading given the specified File object.

Params:
  • file – the ZIP file to be opened for reading
  • charset –  The charset to be used to decode the ZIP entry name and comment (ignored if the  language
       encoding bit of the ZIP entry's general purpose bit
       flag is set).
Throws:
Since:1.7
/**
     * Opens a ZIP file for reading given the specified File object.
     * @param file the ZIP file to be opened for reading
     * @param charset
     *        The {@linkplain java.nio.charset.Charset charset} to be
     *        used to decode the ZIP entry name and comment (ignored if
     *        the <a href="package-summary.html#lang_encoding"> language
     *        encoding bit</a> of the ZIP entry's general purpose bit
     *        flag is set).
     *
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     *
     * @since 1.7
     */
    public ZipFile(File file, Charset charset) throws IOException
    {
        this(file, OPEN_READ, charset);
    }

    
Returns the zip file comment, or null if none.

Throws:
Returns:the comment string for the zip file, or null if none
/**
     * Returns the zip file comment, or null if none.
     *
     * @return the comment string for the zip file, or null if none
     *
     * @throws IllegalStateException if the zip file has been closed
     *
     * Since 1.7
     */
    public String getComment() {
        synchronized (this) {
            ensureOpen();
            byte[] bcomm = getCommentBytes(jzfile);
            if (bcomm == null)
                return null;
            return zc.toString(bcomm, bcomm.length);
        }
    }

    
Returns the zip file entry for the specified name, or null
if not found.

Params:
  • name – the name of the entry
Throws:
Returns:the zip file entry, or null if not found
/**
     * Returns the zip file entry for the specified name, or null
     * if not found.
     *
     * @param name the name of the entry
     * @return the zip file entry, or null if not found
     * @throws IllegalStateException if the zip file has been closed
     */
    public ZipEntry getEntry(String name) {
        if (name == null) {
            throw new NullPointerException("name");
        }
        long jzentry = 0;
        synchronized (this) {
            ensureOpen();
            jzentry = getEntry(jzfile, zc.getBytes(name), true);
            if (jzentry != 0) {
                // If no entry is found for the specified 'name' and
                // the 'name' does not end with a forward slash '/',
                // the implementation tries to find the entry with a
                // slash '/' appended to the end of the 'name', before
                // returning null. When such entry is found, the name
                // that actually is found (with a slash '/' attached)
                // is used
                // (disabled if jdk.util.zip.ensureTrailingSlash=false)
                ZipEntry ze = ensuretrailingslash ? getZipEntry(null, jzentry)
                                                  : getZipEntry(name, jzentry);
                freeEntry(jzfile, jzentry);
                return ze;
            }
        }
        return null;
    }

    private static native long getEntry(long jzfile, byte[] name,
                                        boolean addSlash);

    // freeEntry releases the C jzentry struct.
    private static native void freeEntry(long jzfile, long jzentry);

    // the outstanding inputstreams that need to be closed,
    // mapped to the inflater objects they use.
    private final Map<InputStream, Inflater> streams = new WeakHashMap<>();

    
Returns an input stream for reading the contents of the specified
zip file entry.

 Closing this ZIP file will, in turn, close all input
streams that have been returned by invocations of this method.

Params:
  • entry – the zip file entry
Throws:
Returns:the input stream for reading the contents of the specified
zip file entry.
/**
     * Returns an input stream for reading the contents of the specified
     * zip file entry.
     *
     * <p> Closing this ZIP file will, in turn, close all input
     * streams that have been returned by invocations of this method.
     *
     * @param entry the zip file entry
     * @return the input stream for reading the contents of the specified
     * zip file entry.
     * @throws ZipException if a ZIP format error has occurred
     * @throws IOException if an I/O error has occurred
     * @throws IllegalStateException if the zip file has been closed
     */
    public InputStream getInputStream(ZipEntry entry) throws IOException {
        if (entry == null) {
            throw new NullPointerException("entry");
        }
        long jzentry = 0;
        ZipFileInputStream in = null;
        synchronized (this) {
            ensureOpen();
            if (!zc.isUTF8() && (entry.flag & EFS) != 0) {
                jzentry = getEntry(jzfile, zc.getBytesUTF8(entry.name), false);
            } else {
                jzentry = getEntry(jzfile, zc.getBytes(entry.name), false);
            }
            if (jzentry == 0) {
                return null;
            }
            in = new ZipFileInputStream(jzentry);

            switch (getEntryMethod(jzentry)) {
            case STORED:
                synchronized (streams) {
                    streams.put(in, null);
                }
                return in;
            case DEFLATED:
                // MORE: Compute good size for inflater stream:
                long size = getEntrySize(jzentry) + 2; // Inflater likes a bit of slack
                if (size > 65536) size = 8192;
                if (size <= 0) size = 4096;
                Inflater inf = getInflater();
                InputStream is =
                    new ZipFileInflaterInputStream(in, inf, (int)size);
                synchronized (streams) {
                    streams.put(is, inf);
                }
                return is;
            default:
                throw new ZipException("invalid compression method");
            }
        }
    }

    private class ZipFileInflaterInputStream extends InflaterInputStream {
        private volatile boolean closeRequested = false;
        private boolean eof = false;
        private final ZipFileInputStream zfin;

        ZipFileInflaterInputStream(ZipFileInputStream zfin, Inflater inf,
                int size) {
            super(zfin, inf, size);
            this.zfin = zfin;
        }

        public void close() throws IOException {
            if (closeRequested)
                return;
            closeRequested = true;

            super.close();
            Inflater inf;
            synchronized (streams) {
                inf = streams.remove(this);
            }
            if (inf != null) {
                releaseInflater(inf);
            }
        }

        // Override fill() method to provide an extra "dummy" byte
        // at the end of the input stream. This is required when
        // using the "nowrap" Inflater option.
        protected void fill() throws IOException {
            if (eof) {
                throw new EOFException("Unexpected end of ZLIB input stream");
            }
            len = in.read(buf, 0, buf.length);
            if (len == -1) {
                buf[0] = 0;
                len = 1;
                eof = true;
            }
            inf.setInput(buf, 0, len);
        }

        public int available() throws IOException {
            if (closeRequested)
                return 0;
            long avail = zfin.size() - inf.getBytesWritten();
            return (avail > (long) Integer.MAX_VALUE ?
                    Integer.MAX_VALUE : (int) avail);
        }

        protected void finalize() throws Throwable {
            close();
        }
    }

    /*
     * Gets an inflater from the list of available inflaters or allocates
     * a new one.
     */
    private Inflater getInflater() {
        Inflater inf;
        synchronized (inflaterCache) {
            while (null != (inf = inflaterCache.poll())) {
                if (false == inf.ended()) {
                    return inf;
                }
            }
        }
        return new Inflater(true);
    }

    /*
     * Releases the specified inflater to the list of available inflaters.
     */
    private void releaseInflater(Inflater inf) {
        if (false == inf.ended()) {
            inf.reset();
            synchronized (inflaterCache) {
                inflaterCache.add(inf);
            }
        }
    }

    // List of available Inflater objects for decompression
    private Deque<Inflater> inflaterCache = new ArrayDeque<>();

    
Returns the path name of the ZIP file.

Returns:the path name of the ZIP file
/**
     * Returns the path name of the ZIP file.
     * @return the path name of the ZIP file
     */
    public String getName() {
        return name;
    }

    private class ZipEntryIterator implements Enumeration<ZipEntry>, Iterator<ZipEntry> {
        private int i = 0;

        public ZipEntryIterator() {
            ensureOpen();
        }

        public boolean hasMoreElements() {
            return hasNext();
        }

        public boolean hasNext() {
            synchronized (ZipFile.this) {
                ensureOpen();
                return i < total;
            }
        }

        public ZipEntry nextElement() {
            return next();
        }

        public ZipEntry next() {
            synchronized (ZipFile.this) {
                ensureOpen();
                if (i >= total) {
                    throw new NoSuchElementException();
                }
                long jzentry = getNextEntry(jzfile, i++);
                if (jzentry == 0) {
                    String message;
                    if (closeRequested) {
                        message = "ZipFile concurrently closed";
                    } else {
                        message = getZipMessage(ZipFile.this.jzfile);
                    }
                    throw new ZipError("jzentry == 0" +
                                       ",\n jzfile = " + ZipFile.this.jzfile +
                                       ",\n total = " + ZipFile.this.total +
                                       ",\n name = " + ZipFile.this.name +
                                       ",\n i = " + i +
                                       ",\n message = " + message
                        );
                }
                ZipEntry ze = getZipEntry(null, jzentry);
                freeEntry(jzfile, jzentry);
                return ze;
            }
        }
    }

    
Returns an enumeration of the ZIP file entries.

Throws:
Returns:an enumeration of the ZIP file entries
/**
     * Returns an enumeration of the ZIP file entries.
     * @return an enumeration of the ZIP file entries
     * @throws IllegalStateException if the zip file has been closed
     */
    public Enumeration<? extends ZipEntry> entries() {
        return new ZipEntryIterator();
    }

    
Return an ordered Stream over the ZIP file entries. Entries appear in the Stream in the order they appear in the central directory of the ZIP file. 
Throws:
Returns:an ordered Stream of entries in this ZIP file
Since:1.8
/**
     * Return an ordered {@code Stream} over the ZIP file entries.
     * Entries appear in the {@code Stream} in the order they appear in
     * the central directory of the ZIP file.
     *
     * @return an ordered {@code Stream} of entries in this ZIP file
     * @throws IllegalStateException if the zip file has been closed
     * @since 1.8
     */
    public Stream<? extends ZipEntry> stream() {
        return StreamSupport.stream(Spliterators.spliterator(
                new ZipEntryIterator(), size(),
                Spliterator.ORDERED | Spliterator.DISTINCT |
                        Spliterator.IMMUTABLE | Spliterator.NONNULL), false);
    }

    private ZipEntry getZipEntry(String name, long jzentry) {
        ZipEntry e = new ZipEntry();
        e.flag = getEntryFlag(jzentry);  // get the flag first
        if (name != null) {
            e.name = name;
        } else {
            byte[] bname = getEntryBytes(jzentry, JZENTRY_NAME);
            if (bname == null) {
                e.name = "";             // length 0 empty name
            } else if (!zc.isUTF8() && (e.flag & EFS) != 0) {
                e.name = zc.toStringUTF8(bname, bname.length);
            } else {
                e.name = zc.toString(bname, bname.length);
            }
        }
        e.xdostime = getEntryTime(jzentry);
        e.crc = getEntryCrc(jzentry);
        e.size = getEntrySize(jzentry);
        e.csize = getEntryCSize(jzentry);
        e.method = getEntryMethod(jzentry);
        e.setExtra0(getEntryBytes(jzentry, JZENTRY_EXTRA), false);
        byte[] bcomm = getEntryBytes(jzentry, JZENTRY_COMMENT);
        if (bcomm == null) {
            e.comment = null;
        } else {
            if (!zc.isUTF8() && (e.flag & EFS) != 0) {
                e.comment = zc.toStringUTF8(bcomm, bcomm.length);
            } else {
                e.comment = zc.toString(bcomm, bcomm.length);
            }
        }
        return e;
    }

    private static native long getNextEntry(long jzfile, int i);

    
Returns the number of entries in the ZIP file.

Throws:
Returns:the number of entries in the ZIP file
/**
     * Returns the number of entries in the ZIP file.
     * @return the number of entries in the ZIP file
     * @throws IllegalStateException if the zip file has been closed
     */
    public int size() {
        ensureOpen();
        return total;
    }

    
Closes the ZIP file.

 Closing this ZIP file will close all of the input streams previously returned by invocations of the 
getInputStream method. 
Throws:
/**
     * Closes the ZIP file.
     * <p> Closing this ZIP file will close all of the input streams
     * previously returned by invocations of the {@link #getInputStream
     * getInputStream} method.
     *
     * @throws IOException if an I/O error has occurred
     */
    public void close() throws IOException {
        if (closeRequested)
            return;
        closeRequested = true;

        synchronized (this) {
            // Close streams, release their inflaters
            synchronized (streams) {
                if (false == streams.isEmpty()) {
                    Map<InputStream, Inflater> copy = new HashMap<>(streams);
                    streams.clear();
                    for (Map.Entry<InputStream, Inflater> e : copy.entrySet()) {
                        e.getKey().close();
                        Inflater inf = e.getValue();
                        if (inf != null) {
                            inf.end();
                        }
                    }
                }
            }

            // Release cached inflaters
            Inflater inf;
            synchronized (inflaterCache) {
                while (null != (inf = inflaterCache.poll())) {
                    inf.end();
                }
            }

            if (jzfile != 0) {
                // Close the zip file
                long zf = this.jzfile;
                jzfile = 0;

                close(zf);
            }
        }
    }

    
Ensures that the system resources held by this ZipFile object are
released when there are no more references to it.


Since the time when GC would invoke this method is undetermined,
it is strongly recommended that applications invoke the close
method as soon they have finished accessing this ZipFile.
This will prevent holding up system resources for an undetermined
length of time.

Throws:
  • IOException – if an I/O error has occurred
See Also:
/**
     * Ensures that the system resources held by this ZipFile object are
     * released when there are no more references to it.
     *
     * <p>
     * Since the time when GC would invoke this method is undetermined,
     * it is strongly recommended that applications invoke the <code>close</code>
     * method as soon they have finished accessing this <code>ZipFile</code>.
     * This will prevent holding up system resources for an undetermined
     * length of time.
     *
     * @throws IOException if an I/O error has occurred
     * @see    java.util.zip.ZipFile#close()
     */
    protected void finalize() throws IOException {
        close();
    }

    private static native void close(long jzfile);

    private void ensureOpen() {
        if (closeRequested) {
            throw new IllegalStateException("zip file closed");
        }

        if (jzfile == 0) {
            throw new IllegalStateException("The object is not initialized.");
        }
    }

    private void ensureOpenOrZipException() throws IOException {
        if (closeRequested) {
            throw new ZipException("ZipFile closed");
        }
    }

    /*
     * Inner class implementing the input stream used to read a
     * (possibly compressed) zip file entry.
     */
   private class ZipFileInputStream extends InputStream {
        private volatile boolean zfisCloseRequested = false;
        protected long jzentry; // address of jzentry data
        private   long pos;     // current position within entry data
        protected long rem;     // number of remaining bytes within entry
        protected long size;    // uncompressed size of this entry

        ZipFileInputStream(long jzentry) {
            pos = 0;
            rem = getEntryCSize(jzentry);
            size = getEntrySize(jzentry);
            this.jzentry = jzentry;
        }

        public int read(byte b[], int off, int len) throws IOException {
            synchronized (ZipFile.this) {
                long rem = this.rem;
                long pos = this.pos;
                if (rem == 0) {
                    return -1;
                }
                if (len <= 0) {
                    return 0;
                }
                if (len > rem) {
                    len = (int) rem;
                }

                // Check if ZipFile open
                ensureOpenOrZipException();
                len = ZipFile.read(ZipFile.this.jzfile, jzentry, pos, b,
                                   off, len);
                if (len > 0) {
                    this.pos = (pos + len);
                    this.rem = (rem - len);
                }
            }
            if (rem == 0) {
                close();
            }
            return len;
        }

        public int read() throws IOException {
            byte[] b = new byte[1];
            if (read(b, 0, 1) == 1) {
                return b[0] & 0xff;
            } else {
                return -1;
            }
        }

        public long skip(long n) {
            if (n > rem)
                n = rem;
            pos += n;
            rem -= n;
            if (rem == 0) {
                close();
            }
            return n;
        }

        public int available() {
            return rem > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) rem;
        }

        public long size() {
            return size;
        }

        public void close() {
            if (zfisCloseRequested)
                return;
            zfisCloseRequested = true;

            rem = 0;
            synchronized (ZipFile.this) {
                if (jzentry != 0 && ZipFile.this.jzfile != 0) {
                    freeEntry(ZipFile.this.jzfile, jzentry);
                    jzentry = 0;
                }
            }
            synchronized (streams) {
                streams.remove(this);
            }
        }

        protected void finalize() {
            close();
        }
    }

    static {
        sun.misc.SharedSecrets.setJavaUtilZipFileAccess(
            new sun.misc.JavaUtilZipFileAccess() {
                public boolean startsWithLocHeader(ZipFile zip) {
                    return zip.startsWithLocHeader();
                }
             }
        );
    }

    
Returns true if, and only if, the zip file begins with 
LOCSIG. 
/**
     * Returns {@code true} if, and only if, the zip file begins with {@code
     * LOCSIG}.
     */
    private boolean startsWithLocHeader() {
        return locsig;
    }

    private static native long open(String name, int mode, long lastModified,
                                    boolean usemmap) throws IOException;
    private static native int getTotal(long jzfile);
    private static native boolean startsWithLOC(long jzfile);
    private static native int read(long jzfile, long jzentry,
                                   long pos, byte[] b, int off, int len);

    // access to the native zentry object
    private static native long getEntryTime(long jzentry);
    private static native long getEntryCrc(long jzentry);
    private static native long getEntryCSize(long jzentry);
    private static native long getEntrySize(long jzentry);
    private static native int getEntryMethod(long jzentry);
    private static native int getEntryFlag(long jzentry);
    private static native byte[] getCommentBytes(long jzfile);

    private static final int JZENTRY_NAME = 0;
    private static final int JZENTRY_EXTRA = 1;
    private static final int JZENTRY_COMMENT = 2;
    private static native byte[] getEntryBytes(long jzentry, int type);

    private static native String getZipMessage(long jzfile);
}