Get Environment Variables : System Properties « Development « Java Tutorial

1. Java Tutorial
2. Development
3. System Properties

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

public class Main {
  public static void main(String[] args) {
    Map map = System.getenv();

    Set keys = map.keySet();
    Iterator iterator = keys.iterator();
    while (iterator.hasNext()) {
      String key = (String) iterator.next();
      String value = (String) map.get(key);

      System.out.println(key + " = " + value);
    }
  }
}