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*
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* accompanied this code).
*
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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,
* non-blocking <br> I/O</a> facility. </p></li>
*
* </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 name="buffers"> </a>
*
* <blockquote><table cellspacing=1 cellpadding=0 summary="Description of the various buffers">
* <tr><th align="left">Buffers</th><th align="left">Description</th></tr>
* <tr><td valign=top>{@link java.nio.Buffer}</td>
* <td>Position, limit, and capacity;
* <br>clear, flip, rewind, and mark/reset</td></tr>
* <tr><td valign=top> {@link java.nio.ByteBuffer}</td>
* <td>Get/put, compact, views; allocate, wrap</td></tr>
* <tr><td valign=top> {@link java.nio.MappedByteBuffer} </td>
* <td>A byte buffer mapped to a file</td></tr>
* <tr><td valign=top> {@link java.nio.CharBuffer}</td>
* <td>Get/put, compact; allocate, wrap</td></tr>
* <tr><td valign=top> {@link java.nio.DoubleBuffer}</td>
* <td> ' '</td></tr>
* <tr><td valign=top> {@link java.nio.FloatBuffer}</td>
* <td> ' '</td></tr>
* <tr><td valign=top> {@link java.nio.IntBuffer}</td>
* <td> ' '</td></tr>
* <tr><td valign=top> {@link java.nio.LongBuffer}</td>
* <td> ' '</td></tr>
* <tr><td valign=top> {@link java.nio.ShortBuffer}</td>
* <td> ' '</td></tr>
* <tr><td valign=top>{@link java.nio.ByteOrder}</td>
* <td>Typesafe enumeration for byte orders</td></tr>
* </table></blockquote>
*
* <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;