Format an Integer using Java String Format
String.format("%03d", 1) // => "001"
// │││ └── print the number one
// ││└────── ... as a decimal integer
// │└─────── ... minimum of 3 characters wide
// └──────── ... pad with zeroes instead of spaces
See java.util.Formatter for more information.
Use %03d in the format specifier for the integer. The 0 means that the number will be zero-filled if it is less than three (in this case) digits.
See the Formatter docs for other modifiers.