public String toString() {
    return " Value2 [ stateName : " + stateName + " capitalCity : "
        + capitalCity + " population : " + population + " areaInSqKm : "
        + areaInSqKm + " ]";
  }
Sample class for Data DUnit tests with JSON keys and values
geode-junit/src/main/java/org/apache/geode/management/internal/cli/dto/Value2.java