Summarize String.format()

I was preparing my interview, and I realized that I actually don't know how all the formatting works. So here it is:

public static void main(String[] args) {
  System.out.println("******integer format******");
  //if the number of digits is less than 4, the output will 
  //have leading spaces
  System.out.println("**" + String.format("%4d", 123) + "**");
  //if the number of digits is less than 4, the output will 
  //have trailing spaces
  System.out.println("**" + String.format("%-4d", 123) + "**");
  //if the number of digits is less than 4, the output will 
  //have leading zeros
  System.out.println("**" + String.format("%04d", 123) + "**");
  //will print maximum 2 characters of the string
  System.out.println("**" + String.format("%.2s", 123) + "**");
  //String will have at least length of 7, if the total length is 
  //less than 7, trailing space, group by ","
  //"+": including sign 
  System.out.println("**" + String.format("%+,7d",-1234) + "**");
  
  System.out.println("\n******String format******");
  //if the length of string is less than 15, the output will 
  //have trailing spaces
  System.out.println("**" + String.format("%15s", "abcdefghijk") + "**");
  //if the length of string is less than 15, the output will 
  //have leading spaces
  System.out.println("**" + String.format("%-15s", "abcdefghijk") + "**");
  //print at most 8 characters
  System.out.println("**" + String.format("%.8s", "abcdefghijk") + "**");
  
  
  System.out.println("\n******Floating point******");
  //actual number
  System.out.println("**" + String.format("%f", 3.14159) + "**");
  //padded left with zeros
  System.out.println("**" + String.format("%8f", 3.14159) + "**");
  //maximum 8 digits, if total digits is less than 8
  //padded left with zeros
  System.out.println("**" + String.format("%.8f", 3.14159) + "**");
  //total 10 digits, will have trailing blank spaces if total digits
  //is less than 10, at most 3 digits after the decimal point
  System.out.println("**" + String.format("%-10.3f", 3.14159) + "**");
  //total 10 digits, will have leading blank spaces if total digits
  //is less than 10, at most 3 digits after the decimal point
  System.out.println("**" + String.format("%10.3f", 3.14159) + "**");
  
  System.out.println("\n******time date******");
  //Calendar c = Calendar.getInstance();
  //year, the month with index 2 starting from 0 (0: January), date
  Calendar c = new GregorianCalendar(2015, 2, 1, 3, 24, 39);
  //full name of month, date(leading zeros if needed, only for date), 
  //4-digit year
  System.out.println(String.format("%tB %td, %tY", c, c, c));
  //full name of month, date(no leading zero, only for date), 
  //4-digit year
  System.out.println(String.format("%tB %te, %tY", c, c, c));
  //full name of month, date(no leading zero, only for date), 
  //2-digit year
  System.out.println(String.format("%tB %te, %ty", c, c, c));
  //month in two digits, with leading zero if necessary
  System.out.println(String.format("%tm %te, %tY", c, c, c));
  //can only be used on time, no date year can be included
  //12-hour clock : minute
  System.out.println(String.format("%tl:%tM%tp", c, c, c));
  //== %tm/%td/%ty
  System.out.println(String.format("%tD",c));
  System.out.println(String.format("%tm/%td/%ty", c, c, c));
 }