The [ini4j] is a simple Java API for handling configuration files in Windows .ini format. Additionally, the library includes Java Preferences API implementation based on the .ini file.
Configuration management is an integral part of every application. The standard Java API Properties warrants simple configuration management. A bit more complicated configuration can be managed with the standard Java Preferences API since Java version 1.4. There is also another (much more complicated) method of configuration management: managing configuration files in XML format. In this case the standard Java XML API (JAXP) or another XML-based configuration management system, e.g. Jakarta Commons Digester, is used.
The Properties file can't group settings, which is why its services are often not sufficient. The Preferences API can sort settings in a nice tree structure, but the standard implementation uses hidden filesystem directory structures inside the user's home directory. This means that it can't be used for managing configuration files attached to the application. Managing XML configuration files through the JAXP is a tiresome work, and to learn and master a complex XML-based configuration management system is a time-consuming and difficult task.
There is another way not mentioned so far: using good old Windows .ini files. This format allows you to group settings, so it's better than the Properties API, whereas it's considerably easier to manage than XML configuration files. Contrary to the standard Preferences implementation, .ini files can be attached to applications as configuration files without worry. At the time of writing this document a "de facto" .ini file handling Java library doesn't exist. The [ini4j] tries to be one.
It was an important design aspect to use the standard API. Due to this, I chose the standard Preferences API. This means that the [ini4j] package contains a Preferences implementation that realizes a Preferences API on the .ini files. The Preferences tree has only one level that contains the sections of the .ini file. The only [ini4j] specific thing that remains is to create a Preferences tree that means creating an instance of the IniPreferences object. This object corresponds to the .ini file as a Preferences object.
The Properties file is a simple String,String map, while the Ini object is a two-level map. On its first level the String type keys define the Ini.Section type sections. The Ini.Section object itself is a map, a String,String type map of the name/value pairs.