38. RoundingMode.HALF_UP

• Rounding means discarding a fraction of the value.

• The RoundingMode.HALF_UP rounding mode is the one commonly taught at school:

  • if the discarded fraction is >= 0.5, round up;

  • if the discarded fraction is < 0.5, then round down.

• For example, after

  
      BigDecimal bdRounded = bdValue.setScale(0, RoundingMode.HALF_UP);
  
  

  the rounding will be

  
    Input      Rounded value
    -----      -------------
      4.5  ->  5
      1.1  ->  1
  
  

  The zero parameter sets the precision scale to zero decimal points.