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import java.util.Enumeration;
import java.util.Properties;

/**
* FileName : ShowSystemInfo.java
* Comment  : static Properties getProperties(), static String getProperty(String key) 
*          : 현재 시스템 정보를 알아낼 때 사용
*/
public class ShowSystemInfo {
    public static void main(String arr[]){

        /*
         * java.runtime.name     : 자바 실행환경(JRE)의 이름
         * java.runtime.version  : 자바 실행환경의 버전
         * java.vm.version       : 자바 VM의 버전
         * os.name               : 운영체제의 이름
         * java.class.path       : 환경변수 CLASSPATH에 지정된 경로명
         * user.language         : 사용 언어
         * sun.cpu.isalist       : CPU 종류 
        */        
        String attr = "java.runtime.version";
        System.out.println(attr + "=" + System.getProperty(attr));
        
        // 시스템의 추출 가능한 모든 속성 정보를 출력
        Properties prop = System.getProperties();
        Enumeration enums = prop.propertyNames();
        String key;
        while(enums.hasMoreElements()){
            key = (String)enums.nextElement();
            System.out.println(key + "=" + System.getProperty(key));
        }
    }
}

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

/**
* FileName : HashMapTest.java
* Comment  : entrySet() 메소드를 이용하여 원소를 Set 객체로 변환
*            Set 인터페이스의 iterator() 메소드를 이용하여 Iterator 객체를 생성
*            Iterator 객체의 next()메소드가 리턴하는  Map.Entry 객체를 이용하여
*            key값과 value값을 참조
*/
public class HashMapTest {
    public static void main(String[] arr){
        Map sp = new HashMap(System.getProperties());
        Set entries = sp.entrySet();
        Iterator it = entries.iterator();
        Entry entry;
        while(it.hasNext()){
            entry = (Entry) it.next();
            System.out.println(entry.getKey() + " : " + entry.getValue());
        }
        
        Map sp2 = new HashMap();
        sp2.putAll(System.getProperties());
    }
}

# 출력 결과
java.runtime.version=1.6.0_17-b04
java.runtime.name=Java(TM) SE Runtime Environment
sun.boot.library.path=D:\01.WORKS_PROGRAM\JAVA\JDK6.17\jre\bin
java.vm.version=14.3-b01
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.java.launcher=SUN_STANDARD
sun.os.patch.level=
java.vm.specification.name=Java Virtual Machine Specification
user.dir=D:\10.WORKS\01.JAVA\01.MYSPACE\Sunshiny_Engine
java.runtime.version=1.6.0_17-b04
java.awt.graphicsenv=sun.awt.Win32GraphicsEnvironment
java.endorsed.dirs=D:\01.WORKS_PROGRAM\JAVA\JDK6.17\jre\lib\endorsed
os.arch=x86
java.io.tmpdir=C:\Users\SUNSHINY\AppData\Local\Temp\
line.separator=

java.vm.specification.vendor=Sun Microsystems Inc.
user.variant=
os.name=Windows 7
sun.jnu.encoding=MS949
java.library.path=D:\01.WORKS_PROGRAM\JAVA\JDK6.17\bin;.;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;D:/01.WORKS_PROGRAM/JAVA/JDK6.17/bin/../jre/bin/client;D:/01.WORKS_PROGRAM/JAVA/JDK6.17/bin/../jre/bin;D:\oracle\product\11.2.0\dbhome_1\bin;C:\Program Files\Common Files\NetSarang;D:\oracle\product\10.2.0\client_1\bin;D:\01.WORKS_PROGRAM\JAVA\JDK6.17\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0;C:\Program Files\ESTsoft\ALZip;D:\01.WORKS_PROGRAM\APM_Setup\Server\Apache\bin;D:\01.WORKS_PROGRAM\APM_Setup\Server\MySQL5\bin;D:\01.WORKS_PROGRAM\APM_Setup\Server\PHP5;C:\Program Files\TortoiseSVN\bin;C:\Program Files\QuickTime\QTSystem\;C:\Program Files\ESTsoft\ALZip;D:\01.WORKS_PROGRAM\apache-tomcat-5.5.26/common/lib;D:\oracle\product\11.2.0\dbhome_1\BIN;D:\oracle\SqlQuery\test01;C:\Program Files\ESTsoft\ALSee
java.specification.name=Java Platform API Specification
java.class.version=50.0
sun.management.compiler=HotSpot Client Compiler
os.version=6.1
user.home=C:\Users\SUNSHINY
user.timezone=
java.awt.printerjob=sun.awt.windows.WPrinterJob
file.encoding=MS949
java.specification.version=1.6
user.name=SUNSHINY
java.class.path=D:\10.WORKS\01.JAVA\01.MYSPACE\Sunshiny_Engine\bin;D:\10.WORKS\01.JAVA\01.MYSPACE\Sunshiny_Engine\lib\classes12.jar;D:\10.WORKS\01.JAVA\01.MYSPACE\Sunshiny_Engine\lib\commons-lang-2.4.jar;D:\10.WORKS\01.JAVA\01.MYSPACE\Sunshiny_Engine\lib\commons-logging.jar;D:\10.WORKS\01.JAVA\01.MYSPACE\Sunshiny_Engine\lib\commons-net-2.0.jar;D:\10.WORKS\01.JAVA\01.MYSPACE\Sunshiny_Engine\lib\mail.jar;D:\10.WORKS\01.JAVA\01.MYSPACE\Sunshiny_Engine\lib\servlet-api.jar;D:\10.WORKS\01.JAVA\01.MYSPACE\Sunshiny_Engine\lib\sinetfactory.jar;D:\01.WORKS_PROGRAM\JAVA\JDK6.17\jre\lib\rt.jar
java.vm.specification.version=1.0
sun.arch.data.model=32
java.home=D:\01.WORKS_PROGRAM\JAVA\JDK6.17\jre
java.specification.vendor=Sun Microsystems Inc.
user.language=ko
awt.toolkit=sun.awt.windows.WToolkit
java.vm.info=mixed mode, sharing
java.version=1.6.0_17
java.ext.dirs=D:\01.WORKS_PROGRAM\JAVA\JDK6.17\jre\lib\ext;C:\Windows\Sun\Java\lib\ext
sun.boot.class.path=D:\01.WORKS_PROGRAM\JAVA\JDK6.17\jre\lib\resources.jar;D:\01.WORKS_PROGRAM\JAVA\JDK6.17\jre\lib\rt.jar;D:\01.WORKS_PROGRAM\JAVA\JDK6.17\jre\lib\sunrsasign.jar;D:\01.WORKS_PROGRAM\JAVA\JDK6.17\jre\lib\jsse.jar;D:\01.WORKS_PROGRAM\JAVA\JDK6.17\jre\lib\jce.jar;D:\01.WORKS_PROGRAM\JAVA\JDK6.17\jre\lib\charsets.jar;D:\01.WORKS_PROGRAM\JAVA\JDK6.17\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.desktop=windows
sun.cpu.isalist=pentium_pro+mmx pentium_pro pentium+mmx pentium i486 i386 i86