code: public static Number getDefaultValue(Class<? extends Number> cls)
          {
          if (cls == null)
              {
              throw new IllegalArgumentException("Class argument cannot be null.");
              }
  
          return cls.equals(Integer.class)    ? INT_ZERO
               : cls.equals(Long.class)       ? LONG_ZERO
               : cls.equals(Double.class)     ? DOUBLE_ZERO
               : cls.equals(Float.class)      ? FLOAT_ZERO
               : cls.equals(BigInteger.class) ? BIGINTEGER_ZERO
               : cls.equals(BigDecimal.class) ? BIGDECIMAL_ZERO
               : cls.equals(Short.class)      ? SHORT_ZERO
               : cls.equals(Byte.class)       ? BYTE_ZERO
               : null;
          }
docs: Return default value (zero) for the specified numeric type.
  
  @param cls  numeric type
  
  @return default value (zero) for the specified numeric type