Applied to strings, the precision specifier specifies the maximum field length : Number Format « Data Type « Java Tutorial

1. Java Tutorial
2. Data Type
3. Number Format

For example, %5.7s displays a string at least five and not exceeding seven characters long. If the string is longer than the maximum field width, the end characters will be truncated.

import java.util.Formatter;

public class MainClass {
  public static void main(String args[]) {
    Formatter fmt;

    fmt = new Formatter();
    fmt.format("%5.7s", "abcdefghijklmn");
    System.out.println(fmt);
    
    fmt = new Formatter();
    fmt.format("%5.7s", "abc");
    System.out.println(fmt);
    
  }
}

abcdefg
abc