What Is Character Encoding?

This section provides introductions on what is a character encoding - A map scheme between code points of a code character set and sequences of bytes.

Character Encoding: A map scheme between code points of a code character set and sequences of bytes.

Coded Character Set: A character set in which each character has an assigned a code point (i.e. an integral number).

Code Point: An integral number assigned to a character in a coded character set.

Unicode: A coded character set that contains all characters used in the written languages of the world and special symbols.

As of 1.8, JDK supports Unicode 6.2 with the following primitive types and classes:

char - A primitive type with 16-bit storage size, which was perfectly designed to store the code point value of a single Basic Multilingual Plane (BMP) Unicode character ranging from U+0000 to U+FFFF,

int - A primitive type with 32-bit storage size, which is borrowed to handle the code point value of any Unicode character ranging from U+0000 to U+10FFFF.

java.lang.Character - A built-in class that wraps a value of the primitive type char in an object. The Character class was perfectly designed to represent a single BMP character as an object. The Character class also provides some useful static methods for managing individual BMP characters.

java.lang.String - A built-in class that wraps an array of primitive type char (char[]) in an object. A Unicode character string can be stored in a String object using the UTF-16BE encoding, where a BMP character (code value in the range of U+0000 to U+FFFF) is represented by a single char[] element and a supplement supplementary character (code value in the range of U+10000 to U+10FFFF) is represented by two char[] elements called surrogate char pair.

Last update: 2014.

Table of Contents

 About This JDK Tutorial Book

 Downloading and Installing JDK 1.8.0 on Windows

 Downloading and Installing JDK 1.7.0 on Windows

 Downloading and Installing JDK 1.6.2 on Windows

 Java Date-Time API

 Date, Time and Calendar Classes

 Date and Time Object and String Conversion

 Number Object and Numeric String Conversion

 Locales, Localization Methods and Resource Bundles

 Calling and Importing Classes Defined in Unnamed Packages

 HashSet, Vector, HashMap and Collection Classes

Character Set Encoding Classes and Methods

What Is Character Encoding?

 Supported Character Encodings in JDK

 Charset.encode() - Method to Encode Characters

 Running EncodingSampler.java with CP1252 Encoding

 Running EncodingSampler.java with ISO-8859-1 and US-ASCII

 Running EncodingSampler.java with UTF-8, UTF-16, UTF16-BE

 Running EncodingSampler.java with GB18030

 Charset.decode() - Method to Decode Byte Sequences

 Character Set Encoding Maps

 Encoding Conversion Programs for Encoded Text Files

 Socket Network Communication

 Datagram Network Communication

 DOM (Document Object Model) - API for XML Files

 SAX (Simple API for XML)

 DTD (Document Type Definition) - XML Validation

 XSD (XML Schema Definition) - XML Validation

 XSL (Extensible Stylesheet Language)

 Message Digest Algorithm Implementations in JDK

 Private key and Public Key Pair Generation

 PKCS#8/X.509 Private/Public Encoding Standards

 Digital Signature Algorithm and Sample Program

 "keytool" Commands and "keystore" Files

 KeyStore and Certificate Classes

 Secret Key Generation and Management

 Cipher - Secret Key Encryption and Decryption

 The SSL (Secure Socket Layer) Protocol

 SSL Socket Communication Testing Programs

 SSL Client Authentication

 HTTPS (Hypertext Transfer Protocol Secure)

 Outdated Tutorials

 References

 PDF Printing Version