Module java.base
Package java.util.jar

# Class JarInputStream

java.lang.Object
java.io.InputStream
java.io.FilterInputStream
java.util.zip.InflaterInputStream
java.util.zip.ZipInputStream
java.util.jar.JarInputStream

All Implemented Interfaces:
  `Closeable`, `AutoCloseable`

public class JarInputStream extends ZipInputStream
The `JarInputStream` class is used to read the contents of a JAR file from any input stream. It extends the class `java.util.zip.ZipInputStream` with support for reading an optional `Manifest` entry. The `Manifest` can be used to store meta-information about the JAR file and its entries.

Since:
  1.2
See Also:
  - `Manifest`
  - `ZipInputStream`

## Field Summary

Fields
Modifier and Type
Field
Description
`static final int`
`CENATT`
Central directory (CEN) header internal file attributes field offset.
`static final int`
`CENATX`
Central directory (CEN) header external file attributes field offset.
`static final int`
`CENCOM`
Central directory (CEN) header comment length field offset.
`static final int`
`CENCRC`
Central directory (CEN) header uncompressed file crc-32 value field offset.
`static final int`
`CENDSK`
Central directory (CEN) header disk number start field offset.
`static final int`
`CENEXT`
Central directory (CEN) header extra field length field offset.
`static final int`
`CENFLG`
Central directory (CEN) header encrypt, decrypt flags field offset.
`static final int`
`CENHDR`
Central directory (CEN) header size in bytes (including signature).
`static final int`
`CENHOW`
Central directory (CEN) header compression method field offset.
`static final int`
`CENLEN`
Central directory (CEN) header uncompressed size field offset.
`static final int`
`CENNAM`
Central directory (CEN) header filename length field offset.
`static final int`
`CENOFF`
Central directory (CEN) header LOC header offset field offset.
`static final long`
`CENSIG`
Central directory (CEN) header signature.
`static final int`
`CENSIZ`
Central directory (CEN) header compressed size field offset.
`static final int`
`CENTIM`
Central directory (CEN) header modification time field offset.
`static final int`
`CENVEM`
Central directory (CEN) header version made by field offset.
`static final int`
`CENVER`
Central directory (CEN) header version needed to extract field offset.
`static final int`
`ENDCOM`
End of central directory (END) header zip file comment length field offset.
`static final int`
`ENDHDR`
End of central directory (END) header size in bytes (including signature).
`static final int`
`ENDOFF`
End of central directory (END) header offset for the first CEN header field offset.
`static final long`
`ENDSIG`
End of central directory (END) header signature.
`static final int`
`ENDSIZ`
End of central directory (END) header central directory size in bytes field offset.
`static final int`
`ENDSUB`
End of central directory (END) header number of entries on this disk field offset.
`static final int`
`ENDTOT`
End of central directory (END) header total number of entries field offset.
`static final int`
`EXTCRC`
Extra local (EXT) header uncompressed file crc-32 value field offset.
`static final int`
`EXTHDR`
Extra local (EXT) header size in bytes (including signature).
`static final int`
`EXTLEN`
Extra local (EXT) header uncompressed size field offset.
`static final long`
`EXTSIG`
Extra local (EXT) header signature.
`static final int`
`EXTSIZ`
Extra local (EXT) header compressed size field offset.
`static final int`
`LOCCRC`
Local file (LOC) header uncompressed file crc-32 value field offset.
`static final int`
`LOCEXT`
Local file (LOC) header extra field length field offset.
`static final int`
`LOCFLG`
Local file (LOC) header general purpose bit flag field offset.
`static final int`
`LOCHDR`
Local file (LOC) header size in bytes (including signature).
`static final int`
`LOCHOW`
Local file (LOC) header compression method field offset.
`static final int`
`LOCLEN`
Local file (LOC) header uncompressed size field offset.
`static final int`
`LOCNAM`
Local file (LOC) header filename length field offset.
`static final long`
`LOCSIG`
Local file (LOC) header signature.
`static final int`
`LOCSIZ`
Local file (LOC) header compressed size field offset.
`static final int`
`LOCTIM`
Local file (LOC) header modification time field offset.
`static final int`
`LOCVER`
Local file (LOC) header version needed to extract field offset.

### Fields declared in class java.util.zip.InflaterInputStream

`buf, inf, len`

### Fields declared in class java.io.FilterInputStream

`in`

## Constructor Summary

Constructors
Constructor
Description
`JarInputStream(InputStream in)`
Creates a new `JarInputStream` and reads the optional manifest.
`JarInputStream(InputStream in, boolean verify)`
Creates a new `JarInputStream` and reads the optional manifest.

## Method Summary

Modifier and Type
Method
Description
`protected ZipEntry`
`createZipEntry(String name)`
Creates a new `JarEntry` (`ZipEntry`) for the specified JAR file entry name.
`Manifest`
`getManifest()`
Returns the `Manifest` for this JAR file, or `null` if none.
`ZipEntry`
`getNextEntry()`
Reads the next ZIP file entry and positions the stream at the beginning of the entry data.
`JarEntry`
`getNextJarEntry()`
Reads the next JAR file entry and positions the stream at the beginning of the entry data.
`int`
`read(byte[] b, int off, int len)`
Reads from the current JAR file entry into an array of bytes.

### Methods declared in class java.util.zip.ZipInputStream

`available, close, closeEntry, skip`

### Methods declared in class java.util.zip.InflaterInputStream

`fill, mark, markSupported, read, reset`

### Methods declared in class java.io.FilterInputStream

`read`

### Methods declared in class java.io.InputStream

`nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo`

### Methods declared in class java.lang.Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

## Field Details

### LOCSIG

static final long LOCSIG
Local file (LOC) header signature.

See Also:
  - Constant Field Values

### EXTSIG

static final long EXTSIG
Extra local (EXT) header signature.

See Also:
  - Constant Field Values

### CENSIG

static final long CENSIG
Central directory (CEN) header signature.

See Also:
  - Constant Field Values

### ENDSIG

static final long ENDSIG
End of central directory (END) header signature.

See Also:
  - Constant Field Values

### LOCHDR

static final int LOCHDR
Local file (LOC) header size in bytes (including signature).

See Also:
  - Constant Field Values

### EXTHDR

static final int EXTHDR
Extra local (EXT) header size in bytes (including signature).

See Also:
  - Constant Field Values

### CENHDR

static final int CENHDR
Central directory (CEN) header size in bytes (including signature).

See Also:
  - Constant Field Values

### ENDHDR

static final int ENDHDR
End of central directory (END) header size in bytes (including signature).

See Also:
  - Constant Field Values

### LOCVER

static final int LOCVER
Local file (LOC) header version needed to extract field offset.

See Also:
  - Constant Field Values

### LOCFLG

static final int LOCFLG
Local file (LOC) header general purpose bit flag field offset.

See Also:
  - Constant Field Values

### LOCHOW

static final int LOCHOW
Local file (LOC) header compression method field offset.

See Also:
  - Constant Field Values

### LOCTIM

static final int LOCTIM
Local file (LOC) header modification time field offset.

See Also:
  - Constant Field Values

### LOCCRC

static final int LOCCRC
Local file (LOC) header uncompressed file crc-32 value field offset.

See Also:
  - Constant Field Values

### LOCSIZ

static final int LOCSIZ
Local file (LOC) header compressed size field offset.

See Also:
  - Constant Field Values

### LOCLEN

static final int LOCLEN
Local file (LOC) header uncompressed size field offset.

See Also:
  - Constant Field Values

### LOCNAM

static final int LOCNAM
Local file (LOC) header filename length field offset.

See Also:
  - Constant Field Values

### LOCEXT

static final int LOCEXT
Local file (LOC) header extra field length field offset.

See Also:
  - Constant Field Values

### EXTCRC

static final int EXTCRC
Extra local (EXT) header uncompressed file crc-32 value field offset.

See Also:
  - Constant Field Values

### EXTSIZ

static final int EXTSIZ
Extra local (EXT) header compressed size field offset.

See Also:
  - Constant Field Values

### EXTLEN

static final int EXTLEN
Extra local (EXT) header uncompressed size field offset.

See Also:
  - Constant Field Values

### CENVEM

static final int CENVEM
Central directory (CEN) header version made by field offset.

See Also:
  - Constant Field Values

### CENVER

static final int CENVER
Central directory (CEN) header version needed to extract field offset.

See Also:
  - Constant Field Values

### CENFLG

static final int CENFLG
Central directory (CEN) header encrypt, decrypt flags field offset.

See Also:
  - Constant Field Values

### CENHOW

static final int CENHOW
Central directory (CEN) header compression method field offset.

See Also:
  - Constant Field Values

### CENTIM

static final int CENTIM
Central directory (CEN) header modification time field offset.

See Also:
  - Constant Field Values

### CENCRC

static final int CENCRC
Central directory (CEN) header uncompressed file crc-32 value field offset.

See Also:
  - Constant Field Values

### CENSIZ

static final int CENSIZ
Central directory (CEN) header compressed size field offset.

See Also:
  - Constant Field Values

### CENLEN

static final int CENLEN
Central directory (CEN) header uncompressed size field offset.

See Also:
  - Constant Field Values

### CENNAM

static final int CENNAM
Central directory (CEN) header filename length field offset.

See Also:
  - Constant Field Values

### CENEXT

static final int CENEXT
Central directory (CEN) header extra field length field offset.

See Also:
  - Constant Field Values

### CENCOM

static final int CENCOM
Central directory (CEN) header comment length field offset.

See Also:
  - Constant Field Values

### CENDSK

static final int CENDSK
Central directory (CEN) header disk number start field offset.

See Also:
  - Constant Field Values

### CENATT

static final int CENATT
Central directory (CEN) header internal file attributes field offset.

See Also:
  - Constant Field Values

### CENATX

static final int CENATX
Central directory (CEN) header external file attributes field offset.

See Also:
  - Constant Field Values

### CENOFF

static final int CENOFF
Central directory (CEN) header LOC header offset field offset.

See Also:
  - Constant Field Values

### ENDSUB

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

See Also:
  - Constant Field Values

### ENDTOT

static final int ENDTOT
End of central directory (END) header total number of entries field offset.

See Also:
  - Constant Field Values

### ENDSIZ

static final int ENDSIZ
End of central directory (END) header central directory size in bytes field offset.

See Also:
  - Constant Field Values

### ENDOFF

static final int ENDOFF
End of central directory (END) header offset for the first CEN header field offset.

See Also:
  - Constant Field Values

### ENDCOM

static final int ENDCOM
End of central directory (END) header zip file comment length field offset.

See Also:
  - Constant Field Values

## Constructor Details

### JarInputStream

public JarInputStream(InputStream in) throws IOException
Creates a new `JarInputStream` and reads the optional manifest. If a manifest is present, also attempts to verify the signatures if the JarInputStream is signed.

Parameters:
  `in` - the actual input stream
Throws:
  `IOException` - if an I/O error has occurred

### JarInputStream

public JarInputStream(InputStream in, boolean verify) throws IOException
Creates a new `JarInputStream` and reads the optional manifest. If a manifest is present and verify is true, also attempts to verify the signatures if the JarInputStream is signed.

Parameters:
  `in` - the actual input stream
  `verify` - whether or not to verify the JarInputStream if it is signed.
Throws:
  `IOException` - if an I/O error has occurred

## Method Details

### getManifest

public Manifest getManifest()
Returns the `Manifest` for this JAR file, or `null` if none.

Returns:
  the `Manifest` for this JAR file, or `null` if none.

### getNextEntry

public ZipEntry getNextEntry() throws IOException
Reads the next ZIP file entry and positions the stream at the beginning of the entry data. If verification has been enabled, any invalid signature detected while positioning the stream for the next entry will result in an exception.

Overrides:
  `getNextEntry` in class `ZipInputStream`
Returns:
  the next ZIP file entry, or null if there are no more entries
Throws:
  `ZipException` - if a ZIP file error has occurred
  `IOException` - if an I/O error has occurred
  `SecurityException` - if any of the jar file entries are incorrectly signed.

### getNextJarEntry

public JarEntry getNextJarEntry() throws IOException
Reads the next JAR file entry and positions the stream at the beginning of the entry data. If verification has been enabled, any invalid signature detected while positioning the stream for the next entry will result in an exception.

Returns:
  the next JAR file entry, or null if there are no more entries
Throws:
  `ZipException` - if a ZIP file error has occurred
  `IOException` - if an I/O error has occurred
  `SecurityException` - if any of the jar file entries are incorrectly signed.

### read

public int read(byte[] b, int off, int len) throws IOException
Reads from the current JAR file entry into an array of bytes. If `len` is not zero, the method blocks until some input is available; otherwise, no bytes are read and `0` is returned. If verification has been enabled, any invalid signature on the current entry will be reported at some point before the end of the entry is reached.

Overrides:
  `read` in class `ZipInputStream`
Parameters:
  `b` - the buffer into which the data is read
  `off` - the start offset in the destination array `b`
  `len` - the maximum number of bytes to read
Returns:
  the actual number of bytes read, or -1 if the end of the entry is reached
Throws:
  `NullPointerException` - If `b` is `null`.
  `IndexOutOfBoundsException` - If `off` is negative, `len` is negative, or `len` is greater than `b.length - off`
  `ZipException` - if a ZIP file error has occurred
  `IOException` - if an I/O error has occurred
  `SecurityException` - if any of the jar file entries are incorrectly signed.
See Also:
  - `FilterInputStream.in`

### createZipEntry

protected ZipEntry createZipEntry(String name)
Creates a new `JarEntry` (`ZipEntry`) for the specified JAR file entry name. The manifest attributes of the specified JAR file entry name will be copied to the new `JarEntry`.

Overrides:
  `createZipEntry` in class `ZipInputStream`
Parameters:
  `name` - the name of the JAR/ZIP file entry
Returns:
  the `JarEntry` object just created