code: public double overlapAbsolute(DoubleRange other) {
      if (!intersects(other)) {
        return 0;
      }
      int loCmp = lo.compareTo(other.lo);
      int hiCmp = hi.compareTo(other.hi);
      if (loCmp >= 0 && hiCmp <= 0) {
        return this.length();
      } else if (loCmp <= 0 && hiCmp >= 0) {
        return other.length();
      } else {
        double newLo = (loCmp >= 0) ? this.lo : other.lo;
        double newHi = (hiCmp <= 0) ? this.hi : other.hi;
        return newHi - newLo;
      }
    }
docs: If the interval contains just a single point (i.e. this.lo == this.hi), then the overlap is 0.
  Consider using {@link #overlapRelative(DoubleRange)}.
  
  @param other interval to compare to
  @return 0 if one of the intervals is a single point