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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 *

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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * accompanied this code).

 *

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 *

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/**

 * Defines buffers, which are containers for data, and provides an

 * overview of the other NIO packages.

 *

 *

 * <p> The central abstractions of the NIO APIs are: </p>

 *

 * <ul>

 *

 *   <li><p> <a href="#buffers"><i>Buffers</i></a>, which are containers for data;

 *   </p></li>

 *

 *   <li><p> <a

 *   href="charset/package-summary.html"><i>Charsets</i></a> and their

 *   associated <i>decoders</i> and <i>encoders</i>, <br> which

 *   translate between bytes and Unicode characters; </p></li>

 *

 *   <li><p> <a

 *   href="channels/package-summary.html"><i>Channels</i></a> of

 *   various types, which represent connections <br> to entities

 *   capable of performing I/O operations; and </p></li>

 *

 *   <li><p> <i>Selectors</i> and <i>selection keys</i>, which

 *   together with <br> <i>selectable channels</i> define a <a

 *   href="channels/package-summary.html#multiplex">multiplexed,

 *

 *  </ul>

 *

 * <p> The {@code java.nio} package defines the buffer classes, which

 * are used throughout the NIO APIs.  The charset API is defined in

 * the {@link java.nio.charset} package, and the channel and selector

 * APIs are defined in the {@link java.nio.channels} package.  Each of

 * these subpackages has its own service-provider (SPI) subpackage,

 * the contents of which can be used to extend the platform's default

 * implementations or to construct alternative implementations.

 *

 * <a id="buffers"> </a>

 *

 *     <caption style="display:none">Description of the various buffers</caption>

 *       <td>Position, limit, and capacity;

 *       <td>A byte buffer mapped to a file</td></tr>

 *

 * <p> A <i>buffer</i> is a container for a fixed amount of data of a

 * specific primitive type.  In addition to its content a buffer has a

 * <i>position</i>, which is the index of the next element to be read

 * or written, and a <i>limit</i>, which is the index of the first

 * element that should not be read or written.  The base {@link

 * java.nio.Buffer} class defines these properties as well as methods

 * for <i>clearing</i>, <i>flipping</i>, and <i>rewinding</i>, for

 * <i>marking</i> the current position, and for <i>resetting</i> the

 * position to the previous mark.

 *

 * <p> There is a buffer class for each non-boolean primitive type.

 * Each class defines a family of <i>get</i> and <i>put</i> methods

 * for moving data out of and in to a buffer, methods for

 * <i>compacting</i>, <i>duplicating</i>, and <i>slicing</i> a buffer,

 * and static methods for <i>allocating</i> a new buffer as well as

 * for <i>wrapping</i> an existing array into a buffer.

 *

 * <p> Byte buffers are distinguished in that they can be used as the

 * sources and targets of I/O operations.  They also support several

 * features not found in the other buffer classes:

 *

 * <ul>

 *

 *   <li><p> A byte buffer can be allocated as a <a

 *   href="ByteBuffer.html#direct"> <i>direct</i></a> buffer, in which

 *   case the Java virtual machine will make a best effort to perform

 *   native I/O operations directly upon it.  </p></li>

 *

 *   <li><p> A byte buffer can be created by {@link

 *   java.nio.channels.FileChannel#map <i>mapping</i>} a region of a

 *   file directly into memory, in which case a few additional

 *   file-related operations defined in the {@link

 *   java.nio.MappedByteBuffer} class are available.  </p></li>

 *

 *   <li><p> A byte buffer provides access to its content as either a

 *   heterogeneous or homogeneous sequence of <a

 *   href="ByteBuffer.html#bin"><i>binary data</i></a> of any

 *   non-boolean primitive type, in either big-endian or little-endian

 *   <a href="ByteOrder.html">byte order</a>.  </p></li>

 *

 * </ul>

 *

 * <p> Unless otherwise noted, passing a {@code null} argument to a

 * constructor or method in any class or interface in this package

 * will cause a {@link java.lang.NullPointerException

 * NullPointerException} to be thrown.

 *

 * @since 1.4

 * @author Mark Reinhold

 * @author JSR-51 Expert Group

 */

package java.nio;