System.getProperty(String key)

public class test  
{
public static void main(String[] args)  
{
java.util.Enumeration e = System.getProperties().propertyNames();

while(e.hasMoreElements()){
String obj = (String)e.nextElement();

System.out.print(obj + " ===> ");
System.out.println(System.getProperty(obj));
}
}
}


: result
java.runtime.name ===> Java(TM) 2 Runtime Environment, Standard Edition
sun.boot.library.path ===> C:\j2sdk1.4.2_03\jre\bin
java.vm.version ===> 1.4.2_03-b02
java.vm.vendor ===> Sun Microsystems Inc.
java.vendor.url ===> http://java.sun.com/
path.separator ===> ;
java.vm.name ===> Java HotSpot(TM) Client VM
file.encoding.pkg ===> sun.io
user.country ===> KR
sun.os.patch.level ===> Service Pack 4
java.vm.specification.name ===> Java Virtual Machine Specification
user.dir ===> C:\Documents and Settings\Administrator\바탕 화면
java.runtime.version ===> 1.4.2_03-b02
java.awt.graphicsenv ===> sun.awt.Win32GraphicsEnvironment
java.endorsed.dirs ===> C:\j2sdk1.4.2_03\jre\lib\endorsed
os.arch ===> x86
java.io.tmpdir ===> C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\
line.separator ===>

java.vm.specification.vendor ===> Sun Microsystems Inc.
user.variant ===>
os.name ===> Windows 2000
sun.java2d.fontpath ===>
java.library.path ===> C:\j2sdk1.4.2_03\bin;.;C:\WINNT\system32;C:\WINNT;.;C:\j2
sdk1.4.2_03\bin;C:\oracle\ora92\bin;C:\Program Files\Oracle\jre\1.3.1\bin;C:\Pro
gram Files\Oracle\jre\1.1.8\bin;C:\WINNT\system32;C:\WINNT;C:\WINNT\System32\Wbe
m;F:\apache-ant-1.5.3-1\bin;C:\Program Files\SecureCRT\;C:\Program Files\SSH Com
munications Security\SSH Secure Shell
java.specification.name ===> Java Platform API Specification
java.class.version ===> 48.0
java.util.prefs.PreferencesFactory ===> java.util.prefs.WindowsPreferencesFactor
y
os.version ===> 5.0
user.home ===> C:\Documents and Settings\Administrator
user.timezone ===>
java.awt.printerjob ===> sun.awt.windows.WPrinterJob
file.encoding ===> MS949
java.specification.version ===> 1.4
user.name ===> Administrator
java.class.path ===> .;
java.vm.specification.version ===> 1.0
sun.arch.data.model ===> 32
java.home ===> C:\j2sdk1.4.2_03\jre
java.specification.vendor ===> Sun Microsystems Inc.
user.language ===> ko
awt.toolkit ===> sun.awt.windows.WToolkit
java.vm.info ===> mixed mode
java.version ===> 1.4.2_03
java.ext.dirs ===> C:\j2sdk1.4.2_03\jre\lib\ext
sun.boot.class.path ===> C:\j2sdk1.4.2_03\jre\lib\rt.jar;C:\j2sdk1.4.2_03\jre\li
b\i18n.jar;C:\j2sdk1.4.2_03\jre\lib\sunrsasign.jar;C:\j2sdk1.4.2_03\jre\lib\jsse
.jar;C:\j2sdk1.4.2_03\jre\lib\jce.jar;C:\j2sdk1.4.2_03\jre\lib\charsets.jar;C:\j
2sdk1.4.2_03\jre\classes
java.vendor ===> Sun Microsystems Inc.
file.separator ===> \
java.vendor.url.bug ===> http://java.sun.com/cgi-bin/bugreport.cgi
sun.cpu.endian ===> little
sun.io.unicode.encoding ===> UnicodeLittle
sun.cpu.isalist ===> pentium i486 i386


가끔 OS 및 JVM에 의존적인 환경변수들을 가져올 필요가 있습니다.
그럴때, API 레퍼런스를 찾아보면 나오지만, 그래도 정리를 해 봅니다..

Key	Description of Associated Value
java.version	Java Runtime Environment version
java.vendor	Java Runtime Environment vendor
java.vendor.url	Java vendor URL
java.home	Java installation directory
java.vm.specification.version	Java Virtual Machine specification version
java.vm.specification.vendor	Java Virtual Machine specification vendor
java.vm.specification.name	Java Virtual Machine specification name
java.vm.version	Java Virtual Machine implementation version
java.vm.vendor	Java Virtual Machine implementation vendor
java.vm.name	Java Virtual Machine implementation name
java.specification.version	Java Runtime Environment specification version
java.specification.vendor	Java Runtime Environment specification vendor
java.specification.name	Java Runtime Environment specification name
java.class.version	Java class format version number
java.class.path	Java class path
java.library.path	List of paths to search when loading libraries
java.io.tmpdir	Default temp file path
java.compiler	Name of JIT compiler to use
java.ext.dirs	Path of extension directory or directories
os.name	Operating system name
os.arch	Operating system architecture
os.version	Operating system version
file.separator	File separator ("/" on UNIX)
path.separator	Path separator (":" on UNIX)
line.separator	Line separator ("\n" on UNIX)
user.name	User's account name
user.home	User's home directory
user.dir	User's current working directory