How do I display the environment variables?

Author: Deron Eriksson

Description: This Java example shows how to display the environment variables.

Tutorial created using: Windows XP || JDK 1.6.0_04 || Eclipse Web Tools Platform 2.0 (Eclipse 3.3.0)

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By calling the getenv() method of System, we can obtain a map containing the environment variables (ie, the keys) and their values. The EnvironmentVariablesTest class demonstrates this. A TreeMap was used so that we could view the environment variables in sorted order.

EnvironmentVariablesTest.java

package test;

import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;

public class EnvironmentVariablesTest {

	public static void main(String[] args) throws Exception {

		Map envMap = System.getenv();
		SortedMap sortedEnvMap = new TreeMap(envMap);
		Set keySet = sortedEnvMap.keySet();
		for (String key : keySet) {
			String value = envMap.get(key);
			System.out.println("[" + key + "] " + value);
		}

	}

}

The console output of executing EnvironmentVariablesTest is shown here.

Console output

[=::] ::\
[ALLUSERSPROFILE] C:\ProgramData
[APPDATA] C:\Users\Cakes\AppData\Roaming
[COMPUTERNAME] YOSEMITE
[CYGWIN_HOME] C:\dev\cygwin
[ComSpec] C:\Windows\system32\cmd.exe
[CommonProgramFiles] C:\Program Files\Common Files
[FP_NO_HOST_CHECK] NO
[HOMEDRIVE] C:
[HOMEPATH] \Users\Cakes
[JAVA_HOME] C:\dev\jdk1.6.0_04
[LOCALAPPDATA] C:\Users\Cakes\AppData\Local
[LOGONSERVER] \\YOSEMITE
[M2_HOME] C:\dev\apache-maven-2.0.8
[NUMBER_OF_PROCESSORS] 2
[OS] Windows_NT
[OnlineServices] Online Services
[PATHEXT] .COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC
[PCBRAND] Pavilion
[PLATFORM] HPD
[PROCESSOR_ARCHITECTURE] x86
[PROCESSOR_IDENTIFIER] x86 Family 15 Model 107 Stepping 1, AuthenticAMD
[PROCESSOR_LEVEL] 15
[PROCESSOR_REVISION] 6b01
[PUBLIC] C:\Users\Public
[Path] C:\dev\jdk1.6.0_04\bin\..\jre\bin\client;C:\dev\jdk1.6.0_04\bin\..\jre\bin;C:\dev\cygwin\bin;C:\dev\jdk1.6.0_04\bin;C:\dev\apache-maven-2.0.8\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\hp\bin\Python;c:\Program Files\Common Files\Roxio Shared\DLLShared\;c:\Program Files\Common Files\Roxio Shared\9.0\DLLShared\
[ProgramData] C:\ProgramData
[ProgramFiles] C:\Program Files
[RoxioCentral] c:\Program Files\Common Files\Roxio Shared\9.0\Roxio Central33\
[SESSIONNAME] Console
[SystemDrive] C:
[SystemRoot] C:\Windows
[TEMP] C:\Users\Cakes\AppData\Local\Temp
[TMP] C:\Users\Cakes\AppData\Local\Temp
[USERDOMAIN] Yosemite
[USERNAME] Cakes
[USERPROFILE] C:\Users\Cakes
[windir] C:\Windows