Java String.Format() specifier 's' - strange behaviour

I have following code:

String requestString=String.format(Constants.SEARCH_SETS_API,
                             Constants.DEVELOPER_KEY,
                             "ids:".concat(setId),
                             "1");

where

public static final String DEVELOPER_KEY = "3ansrfnt10cggo80";
public static final String SEARCH_SETS_API = 
                                              "http://api.quizlet.com/1.0/sets?"
                                              + "dev_key=%1s&"
                                              + "q=%2s&"
                                              + "sort=开发者_StackOverflow社区alphabetical&"
                                              + "whitespace=off&"
                                              + "page=%3s&"
                                              + "per_page=50&"
                                              + "time_format=unix&"
                                              + "images_only=off&"
                                              + "updated_since=0&"
                                              + "extended=on";

Problem: Problem is that there is "\n" is inserted before %3s specifier in case 3rd argument is 1 or 2 character long like "1", "12" etc. If it is 3 characters long and more like "123" etc no carriage return is inserted.

Question: How to get rid of the carriage return before %3s argument in case it is 1 or 2 characters long?

I think you are looking for %1$s, %2$s, etc. What you specified in your format string is actually padding the inserted values to the length you’re giving, e.g. 1, 2, and 3 characters.