JarOutputStream

AI-generated Key Takeaways

• JarOutputStream is used to write JAR file contents to an output stream, extending ZipOutputStream with Manifest support.

• It can be initialized with or without a Manifest, which provides metadata about the JAR file and its entries.

• putNextEntry is used to start writing a new JAR file entry, closing any previous one and using default compression if unspecified.

• It inherits functionalities from ZipOutputStream, DeflaterOutputStream, FilterOutputStream, and other related classes for stream manipulation and data compression.

public class JarOutputStream extends ZipOutputStream

The JarOutputStream class is used to write the contents of a JAR file to any output stream. It extends the class java.util.zip.ZipOutputStream with support for writing an optional Manifest entry. The Manifest can be used to specify meta-information about the JAR file and its entries.

See Also

• Manifest
• ZipOutputStream

Inherited Constant Summary

From class java.util.zip.ZipOutputStream

int	CENATT
int	CENATX
int	CENCOM
int	CENCRC
int	CENDSK
int	CENEXT
int	CENFLG
int	CENHDR
int	CENHOW
int	CENLEN
int	CENNAM
int	CENOFF
long	CENSIG
int	CENSIZ
int	CENTIM
int	CENVEM
int	CENVER
int	DEFLATED	Compression method for compressed (DEFLATED) entries.
int	ENDCOM
int	ENDHDR
int	ENDOFF
long	ENDSIG
int	ENDSIZ
int	ENDSUB
int	ENDTOT
int	EXTCRC
int	EXTHDR
int	EXTLEN
long	EXTSIG
int	EXTSIZ
int	LOCCRC
int	LOCEXT
int	LOCFLG
int	LOCHDR
int	LOCHOW
int	LOCLEN
int	LOCNAM
long	LOCSIG
int	LOCSIZ
int	LOCTIM
int	LOCVER
int	STORED	Compression method for uncompressed (STORED) entries.

Inherited Field Summary

From class java.util.zip.DeflaterOutputStream

protected byte[]	buf	Output buffer for writing compressed data.
protected Deflater	def	Compressor for this stream.

From class java.io.FilterOutputStream

protected OutputStream

out

The underlying output stream to be filtered.

Public Constructor Summary

	JarOutputStream(OutputStream out, Manifest man) Creates a new JarOutputStream with the specified Manifest.
	JarOutputStream(OutputStream out) Creates a new JarOutputStream with no manifest.

Public Method Summary

void	putNextEntry(ZipEntry ze) Begins writing a new JAR file entry and positions the stream to the start of the entry data.

Inherited Method Summary

From class java.util.zip.ZipOutputStream

void	close() Closes the ZIP output stream as well as the stream being filtered.
void	closeEntry() Closes the current ZIP entry and positions the stream for writing the next entry.
void	finish() Finishes writing the contents of the ZIP output stream without closing the underlying stream.
void	putNextEntry(ZipEntry e) Begins writing a new ZIP file entry and positions the stream to the start of the entry data.
void	setComment(String comment) Sets the ZIP file comment.
void	setLevel(int level) Sets the compression level for subsequent entries which are DEFLATED.
void	setMethod(int method) Sets the default compression method for subsequent entries.
synchronized void	write(byte[] b, int off, int len) Writes an array of bytes to the current ZIP entry data.

From class java.util.zip.DeflaterOutputStream

void	close() Writes remaining compressed data to the output stream and closes the underlying stream.
void	deflate() Writes next block of compressed data to the output stream.
void	finish() Finishes writing compressed data to the output stream without closing the underlying stream.
void	flush() Flushes the compressed output stream.
void	write(byte[] b, int off, int len) Writes an array of bytes to the compressed output stream.
void	write(int b) Writes a byte to the compressed output stream.

From class java.io.FilterOutputStream

void	close() Closes this output stream and releases any system resources associated with the stream.
void	flush() Flushes this output stream and forces any buffered output bytes to be written out to the stream.
void	write(byte[] b) Writes b.length bytes to this output stream.
void	write(byte[] b, int off, int len) Writes len bytes from the specified byte array starting at offset off to this output stream.
void	write(int b) Writes the specified byte to this output stream.

From class java.io.OutputStream

void	close() Closes this output stream and releases any system resources associated with this stream.
void	flush() Flushes this output stream and forces any buffered output bytes to be written out.
void	write(byte[] b) Writes b.length bytes from the specified byte array to this output stream.
void	write(byte[] b, int off, int len) Writes len bytes from the specified byte array starting at offset off to this output stream.
abstract void	write(int b) Writes the specified byte to this output stream.

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

From interface java.io.Closeable

abstract void

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

From interface java.io.Flushable

abstract void

flush() Flushes this stream by writing any buffered output to the underlying stream.

From interface java.lang.AutoCloseable

abstract void

close() Closes this resource, relinquishing any underlying resources.

Public Constructors

public JarOutputStream (OutputStream out, Manifest man)

Creates a new JarOutputStream with the specified Manifest. The manifest is written as the first entry to the output stream.

Parameters

out	the actual output stream
man	the optional Manifest

Throws

IOException	if an I/O error has occurred

public JarOutputStream (OutputStream out)

Creates a new JarOutputStream with no manifest.

Parameters

out	the actual output stream

Throws

IOException	if an I/O error has occurred

Public Methods

public void putNextEntry (ZipEntry ze)

Begins writing a new JAR file entry and positions the stream to the start of the entry data. This method will also close any previous entry. The default compression method will be used if no compression method was specified for the entry. The current time will be used if the entry has no set modification time.

Parameters

ze	the ZIP/JAR entry to be written

Throws

ZipException	if a ZIP error has occurred
IOException	if an I/O error has occurred