code: private List<VariantAnnotationProto.PopulationFrequency> setPopulationFrequencyParams(){
  
          List<VariantAnnotationProto.PopulationFrequency> populationFrequencyList = new ArrayList<>();
          VariantAnnotationProto.PopulationFrequency.Builder populationFrequency = VariantAnnotationProto.PopulationFrequency.newBuilder();
          populationFrequency.setAltAllele(null);
          populationFrequency.setAltAlleleFreq(0.0f);
          populationFrequency.setAltHomGenotypeFreq(0.0f);
          populationFrequency.setHetGenotypeFreq(0.0f);
          populationFrequency.setPopulation(null);
          populationFrequency.setRefAllele(null);
          populationFrequency.setRefAlleleFreq(0.0f);
          populationFrequency.setRefHomGenotypeFreq(0.0f);
          populationFrequency.setStudy(null);
  
          populationFrequencyList.add(populationFrequency.build());
          return populationFrequencyList;
      }
docs: method to set Population Frequency Parameters
  @return populationFrequencyList