import java.util.Map;
import java.util.Properties;

public class SystemPropertiesTest {
  public static void main(String[] args) {
    Properties property = System.getProperties();
    Map<String, String> env = System.getenv();
    for (Map.Entry<String, String> keyValue : env.entrySet()) {
      if (!property.containsKey(keyValue.getKey())) {
        property.setProperty(keyValue.getKey(), keyValue.getValue());
      }
    }
  }
}