Module java.base
Package java.util.zip

## Class Adler32

- java.lang.Object
- - java.util.zip.Adler32

- All Implemented Interfaces:
    `Checksum`

      public class Adler32
      extends Object
      implements Checksum

  A class that can be used to compute the Adler-32 checksum of a data stream. An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed much faster.

  Passing a `null` argument to a method in this class will cause a `NullPointerException` to be thrown.

  Since:
    1.1

- - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `Adler32()` | Creates a new Adler32 object.

  - ### Method Summary

    Modifier and Type | Method | Description
    --- | --- | ---
    `long` | `getValue()` | Returns the checksum value.
    `void` | `reset()` | Resets the checksum to initial value.
    `void` | `update​(byte[] b, int off, int len)` | Updates the checksum with the specified array of bytes.
    `void` | `update​(int b)` | Updates the checksum with the specified byte (the low eight bits of the argument b).
    `void` | `update​(ByteBuffer buffer)` | Updates the checksum with the bytes from the specified buffer.

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

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

    - ### Methods declared in interface java.util.zip.Checksum

      `update`

- - ### Constructor Detail

    - #### Adler32

          public Adler32()

      Creates a new Adler32 object.

  - ### Method Detail

    - #### update

          public void update​(int b)

      Updates the checksum with the specified byte (the low eight bits of the argument b).
      Specified by:
        `update` in interface `Checksum`
      Parameters:
        `b` - the byte to update the checksum with

    - #### update

          public void update​(byte[] b,
                             int off,
                             int len)

      Updates the checksum with the specified array of bytes.
      Specified by:
        `update` in interface `Checksum`
      Parameters:
        `b` - the byte array to update the checksum with
        `off` - the start offset of the data
        `len` - the number of bytes to use for the update
      Throws:
        `ArrayIndexOutOfBoundsException` - if `off` is negative, or `len` is negative, or `off+len` is negative or greater than the length of the array `b`.

    - #### update

          public void update​(ByteBuffer buffer)

      Updates the checksum with the bytes from the specified buffer. The checksum is updated with the remaining bytes in the buffer, starting at the buffer's position. Upon return, the buffer's position will be updated to its limit; its limit will not have been changed.
      Specified by:
        `update` in interface `Checksum`
      Parameters:
        `buffer` - the ByteBuffer to update the checksum with
      Since:
        1.8

    - #### reset

          public void reset()

      Resets the checksum to initial value.
      Specified by:
        `reset` in interface `Checksum`

    - #### getValue

          public long getValue()

      Returns the checksum value.
      Specified by:
        `getValue` in interface `Checksum`
      Returns:
        the current checksum value