code: @Override
    public void evaluate(DoubleSolution solution) {
      double [] fx = new double[2] ;
      double [] x = new double[getNumberOfVariables()] ;
      for (int i = 0 ; i < getNumberOfVariables(); i++)
      	x[i] = solution.getVariableValue(i) ;
      
      fx[0] = l *(2*x[0]+ Math.sqrt(2.0)*x[1]+ Math.sqrt(x[2])+x[3]) ;
      fx[1] = (f * l / e)*(2/x[0] + 2*Math.sqrt(2)/x[1] - 2*Math.sqrt(2)/x[2] + 2/x[3]);
      
      solution.setObjective(0,fx[0]);
      solution.setObjective(1,fx[1]);
    }
docs: Evaluate() method