Summary

The grouping size of DecimalFormat should not accept negative values.

Problem

grouping size is defined as:

The grouping size is a constant number of digits between the grouping characters, such as 3 for 100,000,000 or 4 for 1,0000,0000.

So it should not take a negative value. Also as it is cast to byte type, the size should not be greater than Byte.MAX_VALUE.

Solution

If an invalid value is specified in DecimalFormat.setGroupingSize(int), throw an IllegalArgumentException.

Specification

Add the following sentence in the last paragraph of the method description.

* Invalid value, i.e., negative or greater than
* {@link java.lang.Byte#MAX_VALUE Byte.MAX_VALUE}, will throw an
* {@code IllegalArgumentException}.

Add the following @throws sentence at the last of the method description.

* @throws IllegalArgumentException if {@code newValue} is negative or
*          greater than {@link java.lang.Byte#MAX_VALUE Byte.MAX_VALUE}