code: private double hypervolume(Front front, Front referenceFront) {
  
      Front invertedFront;
      invertedFront = FrontUtils.getInvertedFront(front);
  
      int numberOfObjectives = referenceFront.getPoint(0).getDimension() ;
  
      // STEP4. The hypervolume (control is passed to the Java version of Zitzler code)
      return this.calculateHypervolume(FrontUtils.convertFrontToArray(invertedFront),
          invertedFront.getNumberOfPoints(), numberOfObjectives);
    }
docs: Returns the hypervolume value of a front of points
  
  @param front        The front
  @param referenceFront    The true pareto front