Defines charsets, decoders, and encoders, for translating between bytes and Unicode characters.

Class name

Description

{@link java.nio.charset.Charset} A named mapping between characters
and bytes
{@link java.nio.charset.CharsetDecoder} Decodes bytes into characters
{@link java.nio.charset.CharsetEncoder}   Encodes characters into bytes
{@link java.nio.charset.CoderResult}   Describes coder results
{@link java.nio.charset.CodingErrorAction}   Describes actions to take when
coding errors are detected

A charset is named mapping between sequences of sixteen-bit Unicode characters and sequences of bytes, in the sense defined in RFC 2278. A decoder is an engine which transforms bytes in a specific charset into characters, and an encoder is an engine which transforms characters into bytes. Encoders and decoders operate on byte and character buffers. They are collectively referred to as coders.

The {@link java.nio.charset.Charset} class defines methods for creating coders for a given charset and for retrieving the various names associated with a charset. It also defines static methods for testing whether a particular charset is supported, for locating charset instances by name, and for constructing a map that contains every charset for which support is available in the current Java virtual machine.

Most users will not use these classes directly; instead they will use the existing charset-related constructors and methods in the {@link java.lang.String} class, together with the existing {@link java.io.InputStreamReader} and {@link java.io.OutputStreamWriter} classes, all of whose implementations have been reworked to make use of the charset facilities defined in this package. A small number of changes have been made to the {@link java.io.InputStreamReader} and {@link java.io.OutputStreamWriter} classes in order to allow explicit charset objects to be specified in the construction of instances of those classes.

Support for new charsets can be made available via the interface defined in the {@link java.nio.charset.spi.CharsetProvider} class in the {@link java.nio.charset.spi} package.

Unless otherwise noted, passing a 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