List system environment using System.getenv()

package javaapplication1;

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

public class JavaApplication1 {

    public static void main(String[] args) {
        
        Map<String, String> envMap = System.getenv();
        
        Iterator<String> iterator = envMap.keySet().iterator();
        while (iterator.hasNext()) {
            String iteratorKey = iterator.next();
            System.out.println(iteratorKey + " : " + envMap.get(iteratorKey));
        }
    }
}

List system environment