Javaproperties

Javaproperties refers to the Java properties mechanism, primarily implemented by the java.util.Properties class. It provides a simple, text-based way to store and retrieve a set of string key-value pairs, typically used for configuration data and localization strings in Java applications.

The standard properties file format uses plain text with lines containing key-value pairs. A line can use an equals sign or a colon as a separator, and whitespace around the separator is ignored. Lines starting with the character # or ! are comments. Keys and values can include spaces and special characters, which are represented using escape sequences (for example, \t, \n, \\, and Unicode escapes like \uXXXX). A backslash at the end of a line indicates the next line is a continuation. In addition to the traditional .properties format, Java also supports an XML representation of properties via the loadFromXML and storeToXML methods.

Key APIs provided by java.util.Properties include:

- load(InputStream) and load(Reader) to read properties from a stream or reader.

- store(OutputStream, String) and store(Writer, String) to write properties with an optional comment.

- getProperty(String key) and setProperty(String key, String value), with getProperty also offering a default value variant.

- propertyNames() to enumerate keys, and methods to work with XML representations.

Encoding issues are a consideration: the standard .properties format uses ISO-8859-1 by default, with non-Latin characters escaped; load(Reader) and XML methods offer alternative handling. Although widely used for configuration, for internationalization ResourceBundle and newer configuration approaches are commonly employed alongside properties.