How to get java AtomicInteger value into three digits

I want to have a counter starting like 001 and 002, 003 likewise. How to get it using java AtomicInteger? I can only get 1,2,3...

AtomicInteger counter = new AtomicInteger(0);
System.out.println(counter.incrementAndGet());

String.format("%03d", 5) would return the string "005". You can shortcut System.out.print(String.format(pattern, values)) to just System.out.printf(pattern, values) (if you want the newline, toss an \n in your pattern string at the end).

This formatting feature works with patterns. % starts a pattern. d means: An integral number (f is for floating point numbers), 3 means: Render at least 3 characters, more if needed, and 0 means: pad it up with zeroes if you need padding because the number is less than 3 characters. Thus, %03d is the pattern for: Render the number, if less than 100 pad with zeroes so it's 3 digits.

Read up on the javadoc of String.format for more info.

As java does only store the number itself internally, you have to do that yourself.
But this is quite easily done with java.lang.String.format(String,Object...) or System.out.printf like this:

AtomicInteger counter = new AtomicInteger(0);
System.out.printf("%03d\n", counter.incrementAndGet());
counter.set(50);
System.out.println(String.format("%03d", counter.incrementAndGet()));
counter.set(100);
System.out.println(String.format("%03d", counter.incrementAndGet()));

Output:

001
051
101

It behaves that way because that's the the AtomicInteger's method toString() returns. If you want zeroes, just make your own method for it. Remember they are now strings.