Java™ Platform
Standard Ed. 6

Package java.nio

Defines buffers, which are containers for data, and provides an overview of the other NIO packages.


Class Summary
Buffer A container for data of a specific primitive type.
ByteBuffer A byte buffer.
ByteOrder A typesafe enumeration for byte orders.
CharBuffer A character buffer.
DoubleBuffer A double buffer.
FloatBuffer A float buffer.
IntBuffer An int buffer.
LongBuffer A long buffer.
MappedByteBuffer A direct byte buffer whose content is a memory-mapped region of a file.
ShortBuffer A short buffer.

Exception Summary
BufferOverflowException Unchecked exception thrown when a relative put operation reaches the target buffer's limit.
BufferUnderflowException Unchecked exception thrown when a relative get operation reaches the source buffer's limit.
InvalidMarkException Unchecked exception thrown when an attempt is made to reset a buffer when its mark is not defined.
ReadOnlyBufferException Unchecked exception thrown when a content-mutation method such as put or compact is invoked upon a read-only buffer.

Package java.nio Description

Defines buffers, which are containers for data, and provides an overview of the other NIO packages.

The central abstractions of the NIO APIs are:

The java.nio package defines the buffer classes, which are used throughout the NIO APIs. The charset API is defined in the java.nio.charset package, and the channel and selector APIs are defined in the 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.



Buffer Position, limit, and capacity;
clear, flip, rewind, and mark/reset
  ByteBuffer Get/put, compact, views; allocate, wrap
    MappedByteBuffer   A byte buffer mapped to a file
  CharBuffer Get/put, compact; allocate, wrap
  DoubleBuffer     ' '
  FloatBuffer     ' '
  IntBuffer     ' '
  LongBuffer     ' '
  ShortBuffer     ' '
ByteOrder Typesafe enumeration for byte orders

A buffer is a container for a fixed amount of data of a specific primitive type. In addition to its content a buffer has a position, which is the index of the next element to be read or written, and a limit, which is the index of the first element that should not be read or written. The base Buffer class defines these properties as well as methods for clearing, flipping, and rewinding, for marking the current position, and for resetting the position to the previous mark.

There is a buffer class for each non-boolean primitive type. Each class defines a family of get and put methods for moving data out of and in to a buffer, methods for compacting, duplicating, and slicing a buffer, and static methods for allocating a new buffer as well as for wrapping an existing array into a buffer.

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:

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


Java™ Platform
Standard Ed. 6

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For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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