import java.util.*;

class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String regex = "\\s+\\z|\\z(?<!\\s)";
		System.out.println("foo.".equals("foo".replaceAll(regex, ".")));
		System.out.println("foo.".equals("foo ".replaceAll(regex, ".")));
		System.out.println("foo.".equals("foo  ".replaceAll(regex, ".")));
		System.out.println(" foo.".equals(" foo  ".replaceAll(regex, ".")));
	}
}