Manifest (Java SE 26 & JDK 26)
Description: declaration: module: java.base, package: java.util.jar, class: Manifest
Keywords: java.util.jar.Manifest class

# Class Manifest

java.lang.Object
java.util.jar.Manifest

All Implemented Interfaces:
  `Cloneable`

public class Manifest extends Object implements Cloneable
The Manifest class is used to maintain Manifest entry names and their associated Attributes. There are main Manifest Attributes as well as per-entry Attributes. For information on the Manifest format, please see the Manifest format specification.

Unless otherwise noted, passing a `null` argument to a constructor or method in this class will cause a `NullPointerException` to be thrown.

Since:
  1.2
External Specifications
  - JAR File Specification
See Also:
  - `Attributes`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Manifest()`
  Constructs a new, empty Manifest.
  `Manifest(InputStream is)`
  Constructs a new Manifest from the specified input stream.
  `Manifest(Manifest man)`
  Constructs a new Manifest that is a copy of the specified Manifest.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `clear()`
  Clears the main Attributes as well as the entries in this Manifest.
  `Object`
  `clone()`
  Returns a shallow copy of this Manifest.
  `boolean`
  `equals(Object o)`
  Returns true if the specified Object is also a Manifest and has the same main Attributes and entries.
  `Attributes`
  `getAttributes(String name)`
  Returns the Attributes for the specified entry name.
  `Map<String, Attributes>`
  `getEntries()`
  Returns a Map of the entries contained in this Manifest.
  `Attributes`
  `getMainAttributes()`
  Returns the main Attributes for the Manifest.
  `int`
  `hashCode()`
  Returns the hash code for this Manifest.
  `void`
  `read(InputStream is)`
  Reads the Manifest from the specified InputStream.
  `void`
  `write(OutputStream out)`
  Writes the Manifest to the specified OutputStream.

  ### Methods declared in class Object

  `finalize, getClass, notify, notifyAll, toString, wait, wait, wait`
  Modifier and Type
  Method
  Description
  `protected void`
  `finalize()`
  Deprecated, for removal: This API element is subject to removal in a future version.
  Finalization is deprecated and subject to removal in a future release.
  `final Class<?>`
  `getClass()`
  Returns the runtime class of this `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()`
  Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
  `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(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.

- ## Constructor Details

  - ### Manifest

    public Manifest()
    Constructs a new, empty Manifest.

  - ### Manifest

    public Manifest(InputStream is) throws IOException
    Constructs a new Manifest from the specified input stream.
    Parameters:
      `is` - the input stream containing manifest data
    Throws:
      `IOException` - if an I/O error has occurred

  - ### Manifest

    public Manifest(Manifest man)
    Constructs a new Manifest that is a copy of the specified Manifest.
    Parameters:
      `man` - the Manifest to copy

- ## Method Details

  - ### getMainAttributes

    public Attributes getMainAttributes()
    Returns the main Attributes for the Manifest.
    Returns:
      the main Attributes for the Manifest

  - ### getEntries

    public Map<String, Attributes> getEntries()
    Returns a Map of the entries contained in this Manifest. Each entry is represented by a String name (key) and associated Attributes (value). The Map permits the `null` key, but no entry with a null key is created by `read(InputStream)`, nor is such an entry written by using `write(OutputStream)`.
    Returns:
      a Map of the entries contained in this Manifest

  - ### getAttributes

    public Attributes getAttributes(String name)
    Returns the Attributes for the specified entry name. This method is defined as:

             return (Attributes)getEntries().get(name)

    Though `null` is a valid `name`, when `getAttributes(null)` is invoked on a `Manifest` obtained from a jar file, `null` will be returned. While jar files themselves do not allow `null`-named attributes, it is possible to invoke `getEntries()` on a `Manifest`, and on that result, invoke `put` with a null key and an arbitrary value. Subsequent invocations of `getAttributes(null)` will return the just-`put` value.

    Note that this method does not return the manifest's main attributes; see `getMainAttributes()`.

    Parameters:
      `name` - entry name
    Returns:
      the Attributes for the specified entry name

  - ### clear

    public void clear()
    Clears the main Attributes as well as the entries in this Manifest.

  - ### write

    public void write(OutputStream out) throws IOException
    Writes the Manifest to the specified OutputStream. Attributes.Name.MANIFEST_VERSION must be set in MainAttributes prior to invoking this method.
    Parameters:
      `out` - the output stream
    Throws:
      `IOException` - if an I/O error has occurred
    See Also:
      - `getMainAttributes()`

  - ### read

    public void read(InputStream is) throws IOException
    Reads the Manifest from the specified InputStream. The entry names and attributes read will be merged in with the current manifest entries.
    Parameters:
      `is` - the input stream
    Throws:
      `IOException` - if an I/O error has occurred

  - ### equals

    public boolean equals(Object o)
    Returns true if the specified Object is also a Manifest and has the same main Attributes and entries.
    Overrides:
      `equals` in class `Object`
    Parameters:
      `o` - the object to be compared
    Returns:
      true if the specified Object is also a Manifest and has the same main Attributes and entries
    See Also:
      - `Object.hashCode()`
      - `HashMap`

  - ### hashCode

    public int hashCode()
    Returns the hash code for this Manifest.
    Overrides:
      `hashCode` in class `Object`
    Returns:
      a hash code value for this object
    See Also:
      - `Object.equals(java.lang.Object)`
      - `System.identityHashCode(Object)`

  - ### clone

    public Object clone()
    Returns a shallow copy of this Manifest. The shallow copy is implemented as follows:

            public Object clone() { return new Manifest(this); }

    Overrides:
      `clone` in class `Object`
    Returns:
      a shallow copy of this Manifest
    See Also:
      - `Cloneable`