@@ -0,0 +1,394 @@
+// http://codingbat.com/prob/p138183%0A%0Apublic String lastChars(String a, String b) %7B%0A  if (a.length() == 0 && b.length() == 0) %7B%0A    return %22@@%22;%0A  %7D%0A  else if (a.length() == 0) %7B%0A   return %22@%22 + b.substring(b.length()-1, b.length()); %0A  %7D%0A  else if (b.length() == 0) %7B%0A    return a.substring(0, 1) + %22@%22;%0A  %7D%0A  else %7B%0A    return a.substring(0, 1) + b.substring(b.length()-1, b.length());%0A  %7D%0A%7D%0A

Create lastChars.java