Simple Pig Latin

pigIt('Pig latin is cool'); // igPay atinlay siay oolcay
pigIt('Hello world !');     // elloHay orldway !

pigIt('Pig latin is cool'); // igPay atinlay siay oolcay
pigIt('Hello world !');     // elloHay orldway !

public class PigLatin {
    public static String pigIt(String str) {
        return str.replaceAll("(\\w)(\\w*)", "$2$1ay");
    }
}

import java.util.Arrays;
import java.util.stream.Collectors;
import java.util.regex.Pattern;

public class PigLatin {
    public static String pigIt(String str) {
        return Arrays.stream(str.trim().split(" "))
                .map(v -> v.matches("[a-zA-Z]+") ? v.substring(1).concat(v.substring(0, 1)).concat("ay") : v)
                .collect(Collectors.joining(" "));
    }
}

import java.util.Arrays;
import java.util.stream.Collectors;

public class PigLatin {
    public static String pigIt(String str) {
        return Arrays.stream(str.split(" ")).map(PigLatin::pigify).collect(Collectors.joining(" "));
    }

    private static String pigify(String word){
        return word.length() > 1 || Character.isLetter(word.charAt(0)) ? word.substring(1) + word.charAt(0) + "ay" : word;
               
    }
}

import static java.lang.Character.*;

public class PigLatin {
    public static String pigIt(String str) {
        StringBuilder result = new StringBuilder();
        
        for (String s : str.split(" ")) {
            char firstLetter = s.charAt(0);

            result.append(s, 1, s.length())
                  .append(firstLetter)
                  .append(isAlphabetic(firstLetter) ? "ay" : "")
                  .append(" ");
        }
        
        return result.substring(0, result.length()-1);
    }
}