SerialBlob (Java Platform SE 8 )
Keywords: javax.sql.rowset.serial.SerialBlob class
Date: 2026-04-17

compact3
javax.sql.rowset.serial

## Class SerialBlob

- java.lang.Object
- - javax.sql.rowset.serial.SerialBlob

- All Implemented Interfaces:
    Serializable, Cloneable, Blob

      public class SerialBlob
      extends Object
      implements Blob, Serializable, Cloneable

  A serialized mapping in the Java programming language of an SQL `BLOB` value.

  The `SerialBlob` class provides a constructor for creating an instance from a `Blob` object. Note that the `Blob` object should have brought the SQL `BLOB` value's data over to the client before a `SerialBlob` object is constructed from it. The data of an SQL `BLOB` value can be materialized on the client as an array of bytes (using the method `Blob.getBytes`) or as a stream of uninterpreted bytes (using the method `Blob.getBinaryStream`).

  `SerialBlob` methods make it possible to make a copy of a `SerialBlob` object as an array of bytes or as a stream. They also make it possible to locate a given pattern of bytes or a `Blob` object within a `SerialBlob` object and to update or truncate a `Blob` object.

  ### Thread safety

  A SerialBlob is not safe for use by multiple concurrent threads. If a SerialBlob is to be used by more than one thread then access to the SerialBlob should be controlled by appropriate synchronization.

  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `SerialBlob(Blob blob)` Constructs a `SerialBlob` object that is a serialized version of the given `Blob` object.
    `SerialBlob(byte[] b)` Constructs a `SerialBlob` object that is a serialized version of the given `byte` array.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `Object` | `clone()` Returns a clone of this `SerialBlob`.
    `boolean` | `equals(Object obj)` Compares this SerialBlob to the specified object.
    `void` | `free()` This method frees the `SeriableBlob` object and releases the resources that it holds.
    `InputStream` | `getBinaryStream()` Returns this `SerialBlob` object as an input stream.
    `InputStream` | `getBinaryStream(long pos, long length)` Returns an `InputStream` object that contains a partial `Blob` value, starting with the byte specified by pos, which is length bytes in length.
    `byte[]` | `getBytes(long pos, int length)` Copies the specified number of bytes, starting at the given position, from this `SerialBlob` object to another array of bytes.
    `int` | `hashCode()` Returns a hash code for this `SerialBlob`.
    `long` | `length()` Retrieves the number of bytes in this `SerialBlob` object's array of bytes.
    `long` | `position(Blob pattern, long start)` Returns the position in this `SerialBlob` object where the given `Blob` object begins, starting the search at the specified position.
    `long` | `position(byte[] pattern, long start)` Returns the position in this `SerialBlob` object where the given pattern of bytes begins, starting the search at the specified position.
    `OutputStream` | `setBinaryStream(long pos)` Retrieves a stream that can be used to write to the `BLOB` value that this `Blob` object represents.
    `int` | `setBytes(long pos, byte[] bytes)` Writes the given array of bytes to the `BLOB` value that this `Blob` object represents, starting at position `pos`, and returns the number of bytes written.
    `int` | `setBytes(long pos, byte[] bytes, int offset, int length)` Writes all or part of the given `byte` array to the `BLOB` value that this `Blob` object represents and returns the number of bytes written.
    `void` | `truncate(long length)` Truncates the `BLOB` value that this `Blob` object represents to be `len` bytes in length.

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

      `finalize, getClass, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### SerialBlob

          public SerialBlob(byte[] b)
                     throws SerialException,
                            SQLException

      Constructs a `SerialBlob` object that is a serialized version of the given `byte` array.

      The new `SerialBlob` object is initialized with the data from the `byte` array, thus allowing disconnected `RowSet` objects to establish serialized `Blob` objects without touching the data source.

      Parameters:
        `b` - the `byte` array containing the data for the `Blob` object to be serialized
      Throws:
        `SerialException` - if an error occurs during serialization
        `SQLException` - if a SQL errors occurs

    - #### SerialBlob

          public SerialBlob(Blob blob)
                     throws SerialException,
                            SQLException

      Constructs a `SerialBlob` object that is a serialized version of the given `Blob` object.

      The new `SerialBlob` object is initialized with the data from the `Blob` object; therefore, the `Blob` object should have previously brought the SQL `BLOB` value's data over to the client from the database. Otherwise, the new `SerialBlob` object will contain no data.

      Parameters:
        `blob` - the `Blob` object from which this `SerialBlob` object is to be constructed; cannot be null.
      Throws:
        `SerialException` - if an error occurs during serialization
        `SQLException` - if the `Blob` passed to this to this constructor is a `null`.
      See Also:
        `Blob`

  - ### Method Detail

    - #### getBytes

          public byte[] getBytes(long pos,
                                 int length)
                          throws SerialException

      Copies the specified number of bytes, starting at the given position, from this `SerialBlob` object to another array of bytes.

      Note that if the given number of bytes to be copied is larger than the length of this `SerialBlob` object's array of bytes, the given number will be shortened to the array's length.

      Specified by:
        `getBytes` in interface `Blob`
      Parameters:
        `pos` - the ordinal position of the first byte in this `SerialBlob` object to be copied; numbering starts at `1`; must not be less than `1` and must be less than or equal to the length of this `SerialBlob` object
        `length` - the number of bytes to be copied
      Returns:
        an array of bytes that is a copy of a region of this `SerialBlob` object, starting at the given position and containing the given number of consecutive bytes
      Throws:
        `SerialException` - if the given starting position is out of bounds; if `free` had previously been called on this object
      See Also:
        `Blob.setBytes(long, byte[])`

    - #### length

          public long length()
                      throws SerialException

      Retrieves the number of bytes in this `SerialBlob` object's array of bytes.
      Specified by:
        `length` in interface `Blob`
      Returns:
        a `long` indicating the length in bytes of this `SerialBlob` object's array of bytes
      Throws:
        `SerialException` - if an error occurs; if `free` had previously been called on this object

    - #### getBinaryStream

          public InputStream getBinaryStream()
                                      throws SerialException

      Returns this `SerialBlob` object as an input stream. Unlike the related method, `setBinaryStream`, a stream is produced regardless of whether the `SerialBlob` was created with a `Blob` object or a `byte` array.
      Specified by:
        `getBinaryStream` in interface `Blob`
      Returns:
        a `java.io.InputStream` object that contains this `SerialBlob` object's array of bytes
      Throws:
        `SerialException` - if an error occurs; if `free` had previously been called on this object
      See Also:
        `setBinaryStream(long)`

    - #### position

          public long position(byte[] pattern,
                               long start)
                        throws SerialException,
                               SQLException

      Returns the position in this `SerialBlob` object where the given pattern of bytes begins, starting the search at the specified position.
      Specified by:
        `position` in interface `Blob`
      Parameters:
        `pattern` - the pattern of bytes for which to search
        `start` - the position of the byte in this `SerialBlob` object from which to begin the search; the first position is `1`; must not be less than `1` nor greater than the length of this `SerialBlob` object
      Returns:
        the position in this `SerialBlob` object where the given pattern begins, starting at the specified position; `-1` if the pattern is not found or the given starting position is out of bounds; position numbering for the return value starts at `1`
      Throws:
        `SerialException` - if an error occurs when serializing the blob; if `free` had previously been called on this object
        `SQLException` - if there is an error accessing the `BLOB` value from the database

    - #### position

          public long position(Blob pattern,
                               long start)
                        throws SerialException,
                               SQLException

      Returns the position in this `SerialBlob` object where the given `Blob` object begins, starting the search at the specified position.
      Specified by:
        `position` in interface `Blob`
      Parameters:
        `pattern` - the `Blob` object for which to search;
        `start` - the position of the byte in this `SerialBlob` object from which to begin the search; the first position is `1`; must not be less than `1` nor greater than the length of this `SerialBlob` object
      Returns:
        the position in this `SerialBlob` object where the given `Blob` object begins, starting at the specified position; `-1` if the pattern is not found or the given starting position is out of bounds; position numbering for the return value starts at `1`
      Throws:
        `SerialException` - if an error occurs when serializing the blob; if `free` had previously been called on this object
        `SQLException` - if there is an error accessing the `BLOB` value from the database

    - #### setBytes

          public int setBytes(long pos,
                              byte[] bytes)
                       throws SerialException,
                              SQLException

      Writes the given array of bytes to the `BLOB` value that this `Blob` object represents, starting at position `pos`, and returns the number of bytes written.
      Specified by:
        `setBytes` in interface `Blob`
      Parameters:
        `pos` - the position in the SQL `BLOB` value at which to start writing. The first position is `1`; must not be less than `1` nor greater than the length of this `SerialBlob` object.
        `bytes` - the array of bytes to be written to the `BLOB` value that this `Blob` object represents
      Returns:
        the number of bytes written
      Throws:
        `SerialException` - if there is an error accessing the `BLOB` value; or if an invalid position is set; if an invalid offset value is set; if `free` had previously been called on this object
        `SQLException` - if there is an error accessing the `BLOB` value from the database
      See Also:
        `getBytes(long, int)`

    - #### setBytes

          public int setBytes(long pos,
                              byte[] bytes,
                              int offset,
                              int length)
                       throws SerialException,
                              SQLException

      Writes all or part of the given `byte` array to the `BLOB` value that this `Blob` object represents and returns the number of bytes written. Writing starts at position `pos` in the `BLOB` value; len bytes from the given byte array are written.
      Specified by:
        `setBytes` in interface `Blob`
      Parameters:
        `pos` - the position in the `BLOB` object at which to start writing. The first position is `1`; must not be less than `1` nor greater than the length of this `SerialBlob` object.
        `bytes` - the array of bytes to be written to the `BLOB` value
        `offset` - the offset in the `byte` array at which to start reading the bytes. The first offset position is `0`; must not be less than `0` nor greater than the length of the `byte` array
        `length` - the number of bytes to be written to the `BLOB` value from the array of bytes bytes.
      Returns:
        the number of bytes written
      Throws:
        `SerialException` - if there is an error accessing the `BLOB` value; if an invalid position is set; if an invalid offset value is set; if number of bytes to be written is greater than the `SerialBlob` length; or the combined values of the length and offset is greater than the Blob buffer; if `free` had previously been called on this object
        `SQLException` - if there is an error accessing the `BLOB` value from the database.
      See Also:
        `getBytes(long, int)`

    - #### setBinaryStream

          public OutputStream setBinaryStream(long pos)
                                       throws SerialException,
                                              SQLException

      Retrieves a stream that can be used to write to the `BLOB` value that this `Blob` object represents. The stream begins at position `pos`. This method forwards the `setBinaryStream()` call to the underlying `Blob` in the event that this `SerialBlob` object is instantiated with a `Blob`. If this `SerialBlob` is instantiated with a `byte` array, a `SerialException` is thrown.
      Specified by:
        `setBinaryStream` in interface `Blob`
      Parameters:
        `pos` - the position in the `BLOB` value at which to start writing
      Returns:
        a `java.io.OutputStream` object to which data can be written
      Throws:
        `SQLException` - if there is an error accessing the `BLOB` value
        `SerialException` - if the SerialBlob in not instantiated with a `Blob` object that supports `setBinaryStream()`; if `free` had previously been called on this object
      See Also:
        `getBinaryStream()`

    - #### truncate

          public void truncate(long length)
                        throws SerialException

      Truncates the `BLOB` value that this `Blob` object represents to be `len` bytes in length.
      Specified by:
        `truncate` in interface `Blob`
      Parameters:
        `length` - the length, in bytes, to which the `BLOB` value that this `Blob` object represents should be truncated
      Throws:
        `SerialException` - if there is an error accessing the Blob value; or the length to truncate is greater that the SerialBlob length; if `free` had previously been called on this object

    - #### getBinaryStream

          public InputStream getBinaryStream(long pos,
                                             long length)
                                      throws SQLException

      Returns an `InputStream` object that contains a partial `Blob` value, starting with the byte specified by pos, which is length bytes in length.
      Specified by:
        `getBinaryStream` in interface `Blob`
      Parameters:
        `pos` - the offset to the first byte of the partial value to be retrieved. The first byte in the `Blob` is at position 1
        `length` - the length in bytes of the partial value to be retrieved
      Returns:
        `InputStream` through which the partial `Blob` value can be read.
      Throws:
        `SQLException` - if pos is less than 1 or if pos is greater than the number of bytes in the `Blob` or if pos + length is greater than the number of bytes in the `Blob`
        `SerialException` - if the `free` method had been previously called on this object
      Since:
        1.6

    - #### free

          public void free()
                    throws SQLException

      This method frees the `SeriableBlob` object and releases the resources that it holds. The object is invalid once the `free` method is called.

      If `free` is called multiple times, the subsequent calls to `free` are treated as a no-op.

      Specified by:
        `free` in interface `Blob`
      Throws:
        `SQLException` - if an error occurs releasing the Blob's resources
      Since:
        1.6

    - #### equals

          public boolean equals(Object obj)

      Compares this SerialBlob to the specified object. The result is `true` if and only if the argument is not `null` and is a `SerialBlob` object that represents the same sequence of bytes as this object.
      Overrides:
        `equals` in class `Object`
      Parameters:
        `obj` - The object to compare this `SerialBlob` against
      Returns:
        `true` if the given object represents a `SerialBlob` equivalent to this SerialBlob, `false` otherwise
      See Also:
        `Object.hashCode()`, `HashMap`

    - #### hashCode

          public int hashCode()

      Returns a hash code for this `SerialBlob`.
      Overrides:
        `hashCode` in class `Object`
      Returns:
        a hash code value for this object.
      See Also:
        `Object.equals(java.lang.Object)`, `System.identityHashCode(java.lang.Object)`

    - #### clone

          public Object clone()

      Returns a clone of this `SerialBlob`. The copy will contain a reference to a clone of the internal byte array, not a reference to the original internal byte array of this `SerialBlob` object. The underlying `Blob` object will be set to null.
      Overrides:
        `clone` in class `Object`
      Returns:
        a clone of this SerialBlob
      See Also:
        `Cloneable`

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