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JarFile  |  API reference  |  Android Developers

public class JarFile
extends ZipFile


The JarFile class is used to read the contents of a jar file from any file that can be opened with java.io.RandomAccessFile. It extends the class java.util.zip.ZipFile with support for reading an optional Manifest entry. The Manifest can be used to specify meta-information about the jar file and its entries.

Unless otherwise noted, passing a null argument to a constructor or method in this class will cause a NullPointerException to be thrown. If the verify flag is on when opening a signed jar file, the content of the file is verified against its signature embedded inside the file. Please note that the verification process does not include validating the signer's certificate. A caller should inspect the return value of JarEntry.getCodeSigners() to further determine if the signature can be trusted.

Summary

Constants

int CENATT

Central directory (CEN) header internal file attributes field offset.

int CENATX

Central directory (CEN) header external file attributes field offset.

int CENCOM

Central directory (CEN) header comment length field offset.

int CENCRC

Central directory (CEN) header uncompressed file crc-32 value field offset.

int CENDSK

Central directory (CEN) header disk number start field offset.

int CENEXT

Central directory (CEN) header extra field length field offset.

int CENFLG

Central directory (CEN) header encrypt, decrypt flags field offset.

int CENHDR

Central directory (CEN) header size in bytes (including signature).

int CENHOW

Central directory (CEN) header compression method field offset.

int CENLEN

Central directory (CEN) header uncompressed size field offset.

int CENNAM

Central directory (CEN) header filename length field offset.

int CENOFF

Central directory (CEN) header LOC header offset field offset.

long CENSIG

Central directory (CEN) header signature.

int CENSIZ

Central directory (CEN) header compressed size field offset.

int CENTIM

Central directory (CEN) header modification time field offset.

int CENVEM

Central directory (CEN) header version made by field offset.

int CENVER

Central directory (CEN) header version needed to extract field offset.

int ENDCOM

End of central directory (END) header zip file comment length field offset.

int ENDHDR

End of central directory (END) header size in bytes (including signature).

int ENDOFF

End of central directory (END) header offset for the first CEN header field offset.

long ENDSIG

End of central directory (END) header signature.

int ENDSIZ

End of central directory (END) header central directory size in bytes field offset.

int ENDSUB

End of central directory (END) header number of entries on this disk field offset.

int ENDTOT

End of central directory (END) header total number of entries field offset.

int EXTCRC

Extra local (EXT) header uncompressed file crc-32 value field offset.

int EXTHDR

Extra local (EXT) header size in bytes (including signature).

int EXTLEN

Extra local (EXT) header uncompressed size field offset.

long EXTSIG

Extra local (EXT) header signature.

int EXTSIZ

Extra local (EXT) header compressed size field offset.

int LOCCRC

Local file (LOC) header uncompressed file crc-32 value field offset.

int LOCEXT

Local file (LOC) header extra field length field offset.

int LOCFLG

Local file (LOC) header general purpose bit flag field offset.

int LOCHDR

Local file (LOC) header size in bytes (including signature).

int LOCHOW

Local file (LOC) header compression method field offset.

int LOCLEN

Local file (LOC) header uncompressed size field offset.

int LOCNAM

Local file (LOC) header filename length field offset.

long LOCSIG

Local file (LOC) header signature.

int LOCSIZ

Local file (LOC) header compressed size field offset.

int LOCTIM

Local file (LOC) header modification time field offset.

int LOCVER

Local file (LOC) header version needed to extract field offset.

String MANIFEST_NAME

The JAR manifest file name.

Inherited constants

From class java.util.zip.ZipFile

int CENATT

Central directory (CEN) header internal file attributes field offset.

int CENATX

Central directory (CEN) header external file attributes field offset.

int CENCOM

Central directory (CEN) header comment length field offset.

int CENCRC

Central directory (CEN) header uncompressed file crc-32 value field offset.

int CENDSK

Central directory (CEN) header disk number start field offset.

int CENEXT

Central directory (CEN) header extra field length field offset.

int CENFLG

Central directory (CEN) header encrypt, decrypt flags field offset.

int CENHDR

Central directory (CEN) header size in bytes (including signature).

int CENHOW

Central directory (CEN) header compression method field offset.

int CENLEN

Central directory (CEN) header uncompressed size field offset.

int CENNAM

Central directory (CEN) header filename length field offset.

int CENOFF

Central directory (CEN) header LOC header offset field offset.

long CENSIG

Central directory (CEN) header signature.

int CENSIZ

Central directory (CEN) header compressed size field offset.

int CENTIM

Central directory (CEN) header modification time field offset.

int CENVEM

Central directory (CEN) header version made by field offset.

int CENVER

Central directory (CEN) header version needed to extract field offset.

int ENDCOM

End of central directory (END) header zip file comment length field offset.

int ENDHDR

End of central directory (END) header size in bytes (including signature).

int ENDOFF

End of central directory (END) header offset for the first CEN header field offset.

long ENDSIG

End of central directory (END) header signature.

int ENDSIZ

End of central directory (END) header central directory size in bytes field offset.

int ENDSUB

End of central directory (END) header number of entries on this disk field offset.

int ENDTOT

End of central directory (END) header total number of entries field offset.

int EXTCRC

Extra local (EXT) header uncompressed file crc-32 value field offset.

int EXTHDR

Extra local (EXT) header size in bytes (including signature).

int EXTLEN

Extra local (EXT) header uncompressed size field offset.

long EXTSIG

Extra local (EXT) header signature.

int EXTSIZ

Extra local (EXT) header compressed size field offset.

int LOCCRC

Local file (LOC) header uncompressed file crc-32 value field offset.

int LOCEXT

Local file (LOC) header extra field length field offset.

int LOCFLG

Local file (LOC) header general purpose bit flag field offset.

int LOCHDR

Local file (LOC) header size in bytes (including signature).

int LOCHOW

Local file (LOC) header compression method field offset.

int LOCLEN

Local file (LOC) header uncompressed size field offset.

int LOCNAM

Local file (LOC) header filename length field offset.

long LOCSIG

Local file (LOC) header signature.

int LOCSIZ

Local file (LOC) header compressed size field offset.

int LOCTIM

Local file (LOC) header modification time field offset.

int LOCVER

Local file (LOC) header version needed to extract field offset.

int OPEN_DELETE

Mode flag to open a zip file and mark it for deletion.

int OPEN_READ

Mode flag to open a zip file for reading.

Public constructors

JarFile(File file)

Creates a new JarFile to read from the specified File object.

JarFile(File file, boolean verify)

Creates a new JarFile to read from the specified File object.

JarFile(File file, boolean verify, int mode)

Creates a new JarFile to read from the specified File object in the specified mode.

JarFile(String name)

Creates a new JarFile to read from the specified file name.

JarFile(String name, boolean verify)

Creates a new JarFile to read from the specified file name.

Public methods

Enumeration<JarEntry> entries()

Returns an enumeration of the zip file entries.

ZipEntry getEntry(String name)

Returns the ZipEntry for the given entry name or null if not found.

InputStream getInputStream(ZipEntry ze)

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

JarEntry getJarEntry(String name)

Returns the JarEntry for the given entry name or null if not found.

Manifest getManifest()

Returns the jar file manifest, or null if none.

Stream<JarEntry> stream()

Returns an ordered Stream over the ZIP file entries.

Inherited methods

From class java.util.zip.ZipFile

void close()

Closes the ZIP file.

Enumeration<? extends ZipEntry> entries()

Returns an enumeration of the ZIP file entries.

String getComment()

Returns the zip file comment, or null if none.

ZipEntry getEntry(String name)

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

InputStream getInputStream(ZipEntry entry)

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

String getName()

Returns the path name of the ZIP file.

int size()

Returns the number of entries in the ZIP file.

Stream<? extends ZipEntry> stream()

Returns an ordered Stream over the ZIP file entries.

From class java.lang.Object

Object clone()

Creates and returns a copy of this object.

boolean equals(Object obj)

Indicates whether some other object is "equal to" this one.

void finalize()

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.

final Class<?> getClass()

Returns the runtime class of this Object.

int hashCode()

Returns a hash code value for the object.

final void notify()

Wakes up a single thread that is waiting on this object's monitor.

final void notifyAll()

Wakes up all threads that are waiting on this object's monitor.

String toString()

Returns a string representation of the object.

final void wait(long timeoutMillis, int nanos)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

final void wait(long timeoutMillis)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

final void wait()

Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

From interface java.io.Closeable

abstract void close()

Closes this stream and releases any system resources associated with it.

From interface java.lang.AutoCloseable

abstract void close()

Closes this resource, relinquishing any underlying resources.

Constants

CENATT

public static final int CENATT

Central directory (CEN) header internal file attributes field offset.

Constant Value: 36 (0x00000024)

CENATX

public static final int CENATX

Central directory (CEN) header external file attributes field offset.

Constant Value: 38 (0x00000026)

CENCOM

public static final int CENCOM

Central directory (CEN) header comment length field offset.

Constant Value: 32 (0x00000020)

CENCRC

public static final int CENCRC

Central directory (CEN) header uncompressed file crc-32 value field offset.

Constant Value: 16 (0x00000010)

CENDSK

public static final int CENDSK

Central directory (CEN) header disk number start field offset.

Constant Value: 34 (0x00000022)

CENEXT

public static final int CENEXT

Central directory (CEN) header extra field length field offset.

Constant Value: 30 (0x0000001e)

CENFLG

public static final int CENFLG

Central directory (CEN) header encrypt, decrypt flags field offset.

Constant Value: 8 (0x00000008)

CENHDR

public static final int CENHDR

Central directory (CEN) header size in bytes (including signature).

Constant Value: 46 (0x0000002e)

CENHOW

public static final int CENHOW

Central directory (CEN) header compression method field offset.

Constant Value: 10 (0x0000000a)

CENLEN

public static final int CENLEN

Central directory (CEN) header uncompressed size field offset.

Constant Value: 24 (0x00000018)

CENNAM

public static final int CENNAM

Central directory (CEN) header filename length field offset.

Constant Value: 28 (0x0000001c)

CENOFF

public static final int CENOFF

Central directory (CEN) header LOC header offset field offset.

Constant Value: 42 (0x0000002a)

CENSIG

public static final long CENSIG

Central directory (CEN) header signature.

Constant Value: 33639248 (0x0000000002014b50)

CENSIZ

public static final int CENSIZ

Central directory (CEN) header compressed size field offset.

Constant Value: 20 (0x00000014)

CENTIM

public static final int CENTIM

Central directory (CEN) header modification time field offset.

Constant Value: 12 (0x0000000c)

CENVEM

public static final int CENVEM

Central directory (CEN) header version made by field offset.

Constant Value: 4 (0x00000004)

CENVER

public static final int CENVER

Central directory (CEN) header version needed to extract field offset.

Constant Value: 6 (0x00000006)

ENDCOM

public static final int ENDCOM

End of central directory (END) header zip file comment length field offset.

Constant Value: 20 (0x00000014)

ENDHDR

public static final int ENDHDR

End of central directory (END) header size in bytes (including signature).

Constant Value: 22 (0x00000016)

ENDOFF

public static final int ENDOFF

End of central directory (END) header offset for the first CEN header field offset.

Constant Value: 16 (0x00000010)

ENDSIG

public static final long ENDSIG

End of central directory (END) header signature.

Constant Value: 101010256 (0x0000000006054b50)

ENDSIZ

public static final int ENDSIZ

End of central directory (END) header central directory size in bytes field offset.

Constant Value: 12 (0x0000000c)

ENDSUB

public static final int ENDSUB

End of central directory (END) header number of entries on this disk field offset.

Constant Value: 8 (0x00000008)

ENDTOT

public static final int ENDTOT

End of central directory (END) header total number of entries field offset.

Constant Value: 10 (0x0000000a)

EXTCRC

public static final int EXTCRC

Extra local (EXT) header uncompressed file crc-32 value field offset.

Constant Value: 4 (0x00000004)

EXTHDR

public static final int EXTHDR

Extra local (EXT) header size in bytes (including signature).

Constant Value: 16 (0x00000010)

EXTLEN

public static final int EXTLEN

Extra local (EXT) header uncompressed size field offset.

Constant Value: 12 (0x0000000c)

EXTSIG

public static final long EXTSIG

Extra local (EXT) header signature.

Constant Value: 134695760 (0x0000000008074b50)

EXTSIZ

public static final int EXTSIZ

Extra local (EXT) header compressed size field offset.

Constant Value: 8 (0x00000008)

LOCCRC

public static final int LOCCRC

Local file (LOC) header uncompressed file crc-32 value field offset.

Constant Value: 14 (0x0000000e)

LOCEXT

public static final int LOCEXT

Local file (LOC) header extra field length field offset.

Constant Value: 28 (0x0000001c)

LOCFLG

public static final int LOCFLG

Local file (LOC) header general purpose bit flag field offset.

Constant Value: 6 (0x00000006)

LOCHDR

public static final int LOCHDR

Local file (LOC) header size in bytes (including signature).

Constant Value: 30 (0x0000001e)

LOCHOW

public static final int LOCHOW

Local file (LOC) header compression method field offset.

Constant Value: 8 (0x00000008)

LOCLEN

public static final int LOCLEN

Local file (LOC) header uncompressed size field offset.

Constant Value: 22 (0x00000016)

LOCNAM

public static final int LOCNAM

Local file (LOC) header filename length field offset.

Constant Value: 26 (0x0000001a)

LOCSIG

public static final long LOCSIG

Local file (LOC) header signature.

Constant Value: 67324752 (0x0000000004034b50)

LOCSIZ

public static final int LOCSIZ

Local file (LOC) header compressed size field offset.

Constant Value: 18 (0x00000012)

LOCTIM

public static final int LOCTIM

Local file (LOC) header modification time field offset.

Constant Value: 10 (0x0000000a)

LOCVER

public static final int LOCVER

Local file (LOC) header version needed to extract field offset.

Constant Value: 4 (0x00000004)

MANIFEST_NAME

public static final String MANIFEST_NAME

The JAR manifest file name.

Constant Value: "META-INF/MANIFEST.MF"

Public constructors

JarFile

public JarFile (File file)

Creates a new JarFile to read from the specified File object. The JarFile will be verified if it is signed.

Parameters
file File: the jar file to be opened for reading
Throws
IOException if an I/O error has occurred
SecurityException if access to the file is denied by the SecurityManager

JarFile

public JarFile (File file, 
                boolean verify)

Creates a new JarFile to read from the specified File object.

Parameters
file File: the jar file to be opened for reading
verify boolean: whether or not to verify the jar file if it is signed.
Throws
IOException if an I/O error has occurred
SecurityException if access to the file is denied by the SecurityManager.

JarFile

public JarFile (File file, 
                boolean verify, 
                int mode)

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

Parameters
file File: the jar file to be opened for reading
verify boolean: whether or not to verify the jar file if it is signed.
mode int: the mode in which the file is to be opened
Throws
IOException if an I/O error has occurred
IllegalArgumentException if the mode argument is invalid
SecurityException if access to the file is denied by the SecurityManager

JarFile

public JarFile (String name)

Creates a new JarFile to read from the specified file name. The JarFile will be verified if it is signed.

Parameters
name String: the name of the jar file to be opened for reading
Throws
IOException if an I/O error has occurred
SecurityException if access to the file is denied by the SecurityManager

JarFile

public JarFile (String name, 
                boolean verify)

Creates a new JarFile to read from the specified file name.

Parameters
name String: the name of the jar file to be opened for reading
verify boolean: whether or not to verify the jar file if it is signed.
Throws
IOException if an I/O error has occurred
SecurityException if access to the file is denied by the SecurityManager

Public methods

getEntry

public ZipEntry getEntry (String name)

Returns the ZipEntry for the given entry name or null if not found.

Parameters
name String: the jar file entry name
Returns
ZipEntry the ZipEntry for the given entry name or null if not found
Throws
IllegalStateException may be thrown if the jar file has been closed

getInputStream

public InputStream getInputStream (ZipEntry ze)

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

Parameters
ze ZipEntry: the zip file entry
Returns
InputStream an input stream for reading the contents of the specified zip file entry
Throws
IOException if an I/O error has occurred
IllegalStateException may be thrown if the jar file has been closed
SecurityException if any of the jar file entries are incorrectly signed.
ZipException if a zip file format error has occurred

getJarEntry

public JarEntry getJarEntry (String name)

Returns the JarEntry for the given entry name or null if not found.

Parameters
name String: the jar file entry name
Returns
JarEntry the JarEntry for the given entry name or null if not found.
Throws
IllegalStateException may be thrown if the jar file has been closed

getManifest

public Manifest getManifest ()

Returns the jar file manifest, or null if none.

Returns
Manifest the jar file manifest, or null if none
Throws
IOException if an I/O error has occurred
IllegalStateException may be thrown if the jar file has been closed

stream

public Stream<JarEntry> stream ()

Returns 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.

Returns
Stream<JarEntry> an ordered Stream of entries in this ZIP file