JarOutputStream (Java Platform SE 8 )
Keywords: java.util.jar.JarOutputStream class
Date: 2026-01-21

compact1, compact2, compact3
java.util.jar

## Class JarOutputStream

- java.lang.Object
- - java.io.OutputStream
  - - java.io.FilterOutputStream
    - - java.util.zip.DeflaterOutputStream
      - - java.util.zip.ZipOutputStream
        - - java.util.jar.JarOutputStream

- All Implemented Interfaces:
    Closeable, Flushable, AutoCloseable

      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.
  Since:
    1.2
  See Also:
    `Manifest`, `ZipOutputStream`

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `CENATT`
    `static int` | `CENATX`
    `static int` | `CENCOM`
    `static int` | `CENCRC`
    `static int` | `CENDSK`
    `static int` | `CENEXT`
    `static int` | `CENFLG`
    `static int` | `CENHDR`
    `static int` | `CENHOW`
    `static int` | `CENLEN`
    `static int` | `CENNAM`
    `static int` | `CENOFF`
    `static long` | `CENSIG`
    `static int` | `CENSIZ`
    `static int` | `CENTIM`
    `static int` | `CENVEM`
    `static int` | `CENVER`
    `static int` | `ENDCOM`
    `static int` | `ENDHDR`
    `static int` | `ENDOFF`
    `static long` | `ENDSIG`
    `static int` | `ENDSIZ`
    `static int` | `ENDSUB`
    `static int` | `ENDTOT`
    `static int` | `EXTCRC`
    `static int` | `EXTHDR`
    `static int` | `EXTLEN`
    `static long` | `EXTSIG`
    `static int` | `EXTSIZ`
    `static int` | `LOCCRC`
    `static int` | `LOCEXT`
    `static int` | `LOCFLG`
    `static int` | `LOCHDR`
    `static int` | `LOCHOW`
    `static int` | `LOCLEN`
    `static int` | `LOCNAM`
    `static long` | `LOCSIG`
    `static int` | `LOCSIZ`
    `static int` | `LOCTIM`
    `static int` | `LOCVER`

    - ### Fields inherited from class java.util.zip.ZipOutputStream

      `DEFLATED, STORED`

    - ### Fields inherited from class java.util.zip.DeflaterOutputStream

      `buf, def`

    - ### Fields inherited from class java.io.FilterOutputStream

      `out`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `JarOutputStream(OutputStream out)` Creates a new `JarOutputStream` with no manifest.
    `JarOutputStream(OutputStream out, Manifest man)` Creates a new `JarOutputStream` with the specified `Manifest`.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `putNextEntry(ZipEntry ze)` Begins writing a new JAR file entry and positions the stream to the start of the entry data.

    - ### Methods inherited from class java.util.zip.ZipOutputStream

      `close, closeEntry, finish, setComment, setLevel, setMethod, write`

    - ### Methods inherited from class java.util.zip.DeflaterOutputStream

      `deflate, flush, write`

    - ### Methods inherited from class java.io.FilterOutputStream

      `write`

    - ### Methods inherited from class java.lang.Object

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

- - ### Field Detail

    - #### LOCSIG

          public static final long LOCSIG

      See Also:
        Constant Field Values

    - #### EXTSIG

          public static final long EXTSIG

      See Also:
        Constant Field Values

    - #### CENSIG

          public static final long CENSIG

      See Also:
        Constant Field Values

    - #### ENDSIG

          public static final long ENDSIG

      See Also:
        Constant Field Values

    - #### LOCHDR

          public static final int LOCHDR

      See Also:
        Constant Field Values

    - #### EXTHDR

          public static final int EXTHDR

      See Also:
        Constant Field Values

    - #### CENHDR

          public static final int CENHDR

      See Also:
        Constant Field Values

    - #### ENDHDR

          public static final int ENDHDR

      See Also:
        Constant Field Values

    - #### LOCVER

          public static final int LOCVER

      See Also:
        Constant Field Values

    - #### LOCFLG

          public static final int LOCFLG

      See Also:
        Constant Field Values

    - #### LOCHOW

          public static final int LOCHOW

      See Also:
        Constant Field Values

    - #### LOCTIM

          public static final int LOCTIM

      See Also:
        Constant Field Values

    - #### LOCCRC

          public static final int LOCCRC

      See Also:
        Constant Field Values

    - #### LOCSIZ

          public static final int LOCSIZ

      See Also:
        Constant Field Values

    - #### LOCLEN

          public static final int LOCLEN

      See Also:
        Constant Field Values

    - #### LOCNAM

          public static final int LOCNAM

      See Also:
        Constant Field Values

    - #### LOCEXT

          public static final int LOCEXT

      See Also:
        Constant Field Values

    - #### EXTCRC

          public static final int EXTCRC

      See Also:
        Constant Field Values

    - #### EXTSIZ

          public static final int EXTSIZ

      See Also:
        Constant Field Values

    - #### EXTLEN

          public static final int EXTLEN

      See Also:
        Constant Field Values

    - #### CENVEM

          public static final int CENVEM

      See Also:
        Constant Field Values

    - #### CENVER

          public static final int CENVER

      See Also:
        Constant Field Values

    - #### CENFLG

          public static final int CENFLG

      See Also:
        Constant Field Values

    - #### CENHOW

          public static final int CENHOW

      See Also:
        Constant Field Values

    - #### CENTIM

          public static final int CENTIM

      See Also:
        Constant Field Values

    - #### CENCRC

          public static final int CENCRC

      See Also:
        Constant Field Values

    - #### CENSIZ

          public static final int CENSIZ

      See Also:
        Constant Field Values

    - #### CENLEN

          public static final int CENLEN

      See Also:
        Constant Field Values

    - #### CENNAM

          public static final int CENNAM

      See Also:
        Constant Field Values

    - #### CENEXT

          public static final int CENEXT

      See Also:
        Constant Field Values

    - #### CENCOM

          public static final int CENCOM

      See Also:
        Constant Field Values

    - #### CENDSK

          public static final int CENDSK

      See Also:
        Constant Field Values

    - #### CENATT

          public static final int CENATT

      See Also:
        Constant Field Values

    - #### CENATX

          public static final int CENATX

      See Also:
        Constant Field Values

    - #### CENOFF

          public static final int CENOFF

      See Also:
        Constant Field Values

    - #### ENDSUB

          public static final int ENDSUB

      See Also:
        Constant Field Values

    - #### ENDTOT

          public static final int ENDTOT

      See Also:
        Constant Field Values

    - #### ENDSIZ

          public static final int ENDSIZ

      See Also:
        Constant Field Values

    - #### ENDOFF

          public static final int ENDOFF

      See Also:
        Constant Field Values

    - #### ENDCOM

          public static final int ENDCOM

      See Also:
        Constant Field Values

  - ### Constructor Detail

    - #### JarOutputStream

          public JarOutputStream(OutputStream out,
                                 Manifest man)
                          throws IOException

      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

    - #### JarOutputStream

          public JarOutputStream(OutputStream out)
                          throws IOException

      Creates a new `JarOutputStream` with no manifest.
      Parameters:
        `out` - the actual output stream
      Throws:
        `IOException` - if an I/O error has occurred

  - ### Method Detail

    - #### putNextEntry

          public void putNextEntry(ZipEntry ze)
                            throws IOException

      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.
      Overrides:
        `putNextEntry` in class `ZipOutputStream`
      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

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