Querying Environment Variables

Question:
How to find out what environment variables are set?

Answer:
By using System.getenv() which returns an unmodifiable string map view of the current system environment.

Code:
import java.util.Map;
 
public class EnvironmentTest {
  public static void main (String[] args) {
    Map<String, String> env = System.getenv();
    for (String envName : env.keySet()) {
      System.out.println(envName + "=" + env.get(envName));
    }
  }
}

Output:
$ java EnvironmentTest
TERM:xterm
GNOME_KEYRING_CONTROL:/tmp/keyring-1HTIOT
XDG_SESSION_PATH:/org/freedesktop/DisplayManager/Session0
SSH_AGENT_PID:1748
SHLVL:1
XFILESEARCHPATH:/usr/dt/app-defaults/%L/Dt
SESSION_MANAGER:local/pats:@/tmp/.ICE-unix/1767,unix/pats:/tmp/.ICE-unix/1767
COLORTERM:Terminal
XDG_SESSION_COOKIE:9f54a81594c5266e4a0ed3cd00000012-1406048016.654947-1739155940
GDMSESSION:xubuntu
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