The AudioSystem class acts as the entry point to the sampled-audio system resources. This class lets you query and access the mixers that are installed on the system. AudioSystem includes a number of methods for converting audio data between different formats, and for translating between audio files and streams. It also provides a method for obtaining a Line directly from the AudioSystem without dealing explicitly with mixers.

Properties can be used to specify the default mixer for specific line types. Both system properties and a properties file are considered. The "sound.properties" properties file is read from an implementation-specific location (typically it is the conf directory in the Java installation directory). The optional "javax.sound.config.file" system property can be used to specify the properties file that will be read as the initial configuration. If a property exists both as a system property and in the properties file, the system property takes precedence. If none is specified, a suitable default is chosen among the available devices. The syntax of the properties file is specified in Properties.load. The following table lists the available property keys and which methods consider them:

Audio System Property Keys

Property Key	Interface	Affected Method(s)
javax.sound.sampled.Clip	Clip	getLine, getClip
javax.sound.sampled.Port	Port	getLine
javax.sound.sampled.SourceDataLine	SourceDataLine	getLine, getSourceDataLine
javax.sound.sampled.TargetDataLine	TargetDataLine	getLine, getTargetDataLine

The property value consists of the provider class name and the mixer name, separated by the hash mark ("#"). The provider class name is the fully-qualified name of a concrete mixer provider class. The mixer name is matched against the String returned by the getName method of Mixer.Info. Either the class name, or the mixer name may be omitted. If only the class name is specified, the trailing hash mark is optional.

If the provider class is specified, and it can be successfully retrieved from the installed providers, the list of Mixer.Info objects is retrieved from the provider. Otherwise, or when these mixers do not provide a subsequent match, the list is retrieved from getMixerInfo to contain all available Mixer.Info objects.

If a mixer name is specified, the resulting list of Mixer.Info objects is searched: the first one with a matching name, and whose Mixer provides the respective line interface, will be returned. If no matching Mixer.Info object is found, or the mixer name is not specified, the first mixer from the resulting list, which provides the respective line interface, will be returned.

For example, the property javax.sound.sampled.Clip with a value "com.sun.media.sound.MixerProvider#SunClip" will have the following consequences when getLine is called requesting a Clip instance: if the class com.sun.media.sound.MixerProvider exists in the list of installed mixer providers, the first Clip from the first mixer with name "SunClip" will be returned. If it cannot be found, the first Clip from the first mixer of the specified provider will be returned, regardless of name. If there is none, the first Clip from the first Mixer with name "SunClip" in the list of all mixers (as returned by getMixerInfo) will be returned, or, if not found, the first Clip of the first Mixer that can be found in the list of all mixers is returned. If that fails, too, an IllegalArgumentException is thrown.