如文件分隔符，默认的文件编码格式等。
public class TestProperties{
public static void main(String[] args){
System.getProperties().list(System.out);
}
}
在我的机子上输出：
C:\java>javac TestProperties.java
C:\java>java TestProperties
-- listing properties --
java.runtime.name=Java(TM) 2 Runtime Environment, Stand...
sun.boot.library.path=C:\Program Files\Java\j2re1.4.2_03\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=CN
sun.os.patch.level=Service Pack 1
java.vm.specification.name=Java Virtual Machine Specification
user.dir=C:\java
java.runtime.version=1.4.2_03-b02
java.awt.graphicsenv=sun.awt.Win32GraphicsEnvironment
java.endorsed.dirs=C:\Program Files\Java\j2re1.4.2_03\li...
os.arch=x86
java.io.tmpdir=C:\DOCUME~1\cwb\LOCALS~1\Temp\
line.separator=
java.vm.specification.vendor=Sun Microsystems Inc.
user.variant=
os.name=Windows XP
sun.java2d.fontpath=
java.library.path=C:\WINDOWS\system32;.;C:\WINDOWS\Syst...
java.specification.name=Java Platform API Specification
java.class.version=48.0
java.util.prefs.PreferencesFactory=java.util.prefs.WindowsPreferencesFac...
os.version=5.1
user.home=C:\Documents and Settings\cwb
user.timezone=
java.awt.printerjob=sun.awt.windows.WPrinterJob
file.encoding=GBK
java.specification.version=1.4
user.name=cwb
java.class.path=d:\j2sdk1.4.2\lib;c:\j2ee1.3.1\lib\j2...
java.vm.specification.version=1.0
sun.arch.data.model=32
java.home=C:\Program Files\Java\j2re1.4.2_03
java.specification.vendor=Sun Microsystems Inc.
user.language=zh
awt.toolkit=sun.awt.windows.WToolkit
java.vm.info=mixed mode
java.version=1.4.2_03
java.ext.dirs=C:\Program Files\Java\j2re1.4.2_03\li...
sun.boot.class.path=C:\Program Files\Java\j2re1.4.2_03\li...
java.vendor=Sun Microsystems Inc.
file.separator=\
java.vendor.url.bug=http://java.sun.com/cgi-bin/bugreport...
sun.cpu.endian=little
sun.io.unicode.encoding=UnicodeLittle
sun.cpu.isalist=pentium i486 i386
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