Java in a Nutshell, 5th Edition

Name

System

Synopsis

This class defines a platform-independent interface to system facilities, including system properties and system input and output streams. All methods and variables of this class are static, and the class cannot be instantiated. Because the methods defined by this class are low-level system methods, most require special permissions and cannot be executed by untrusted code.

getProperty( ) looks up a named property on the system properties list, returning the optionally specified default value if no property definition is found. getProperties( ) returns the entire properties list. setProperties( ) sets a Properties object on the properties list. In Java 1.2 and later, setProperty( ) sets the value of a system property. In Java 5.0, you can clear a property setting with clearProperty( ) . The following table lists system properties that are always defined. Untrusted code may be unable to read some or all of these properties. Additional properties can be defined using the -D option when invoking the Java interpreter.

Property name	Description
file.separator	Platform directory separator character
path.separator	Platform path separator character
line.separator	Platform line separator character(s)
user.name	Current user s account name
user.home	Home directory of current user
user.dir	The current working directory
java.class.path	Where classes are loaded from
java.class.version	Version of the Java class file format
java.compiler ...