Mastering Java: The Ultimate Quiz for 'Thinking in Java'

Which method in the Formatter class guarantees that a field is at least a certain number of characters wide?

1. precision()

2. length()

3. width()

4. format()

The correct answer is: format()

The Formatter class has a method called format() that is used to format data types such as boolean, character, string, numeric and date/time. This method allows for a variety of formatting options, including specifying a minimum width for a field. The other options, precision(), length(), and width(), are not methods of the Formatter class and therefore cannot guarantee a minimum field width. In addition, precision() is used for floating point numbers, length() is used for arrays and collections, and width() is used for setting the overall width of the output. Therefore, D format() is the correct answer for guaranteeing a minimum field width.