Java System properties

import java.util.Arrays;

public class SystemProperties {

    public static void main(String [] args) {
        String [] keys = System.getProperties().keySet()
            .toArray(new String [] {});
        Arrays.sort(keys);
        for (String key: keys) {
            String value = System.getProperty(key);
            System.out.println(key + ": " + value);
        }
    }

}