Consider the fact that words might be separated by more than one space.

in this case yours words[] array will contain these: [sam, , , , i, , , , , am] It means the array has several empty string elements. If in the foreach loop you call the w.substring(0,1) on these empty string elements, it will cause Exceptions. So you need to insert a check before w.substring().

Hi, Varga! How should I use the .trim() method before String first = w.substring(0,1) ? Be more precise! Thank you!

java.lang.StringIndexOutOfBoundsException: String index out of range: 1 at java.lang.String.substring(String.java:1963) at com.codegym.task.task08.task0823.Solution.main(Solution.java:22) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

Hi Cristian! We suppose the input is: "sam i am" = sam, space, space, space, i, space, space, space, space, am . ((10 units!)) = [sam, , , i, , , , am] will be stored in your words[] array after the executing of split("\\s") method, and at this moment you will see exactly this if you print your array for purpose of testing the work of program. More precisely the elements of words[] are the followings: words[0]="sam" // Its length == 3 . words[1]="" // = empty string! Its length == 0 . words[2]="" // = empty string! Its length == 0 . words[3]="i" // Its length == 1 . words[4]="" // = empty string! Its length == 0 . words[5]="" // = empty string! Its length == 0 . words[6]="" // = empty string! Its length == 0 . words[7]="am" // Its length == 2 . ((In total: 8 elements in the words[]!)) The pattern (space) given in the split() method, won't be the part of the splitted strings. Instead we will get a lot of empty strings. After all of this, the prg goes into a loop, and it try to execute the following command on all of the elements of the words[] array: String first = w.substring(0,1); It means, return one piece char from the "w" string, starting at its zero index. But this is impossible, because the length of words[1] == zero. It is an empty string. JVM can not return one piece char to you from this string, because this has zero piece char. In this case you will see the "String Index Out Of Bounds Exception". This is similar to an error. So you need to insert a check condition before w.substring(). "Is this element an empty string or not?" If yes, don't run the substring method on this. Skip it. To these things I referred in my second post at 22:37 yesterday. And i'm sorry, but please forget the trim() method I wrote in my first post (at 22:25)... It doesn't work here. I wish you good coding!:) Gellert.

Thank you so much!

public class Solution { public static void main(String[] args) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String str = reader.readLine(); //Split sentence into words String words[] = str.trim().split("\\s"); String newString = " "; String first = " "; for(String w : words){ if (!w.isEmpty()) { first = w.substring(0,1); //First Letter } String rest = w.substring(1); //Rest of the letters //Concatenete and reassign after //converting the first letter to uppercase newString += first.toUpperCase() + rest + " "; } //trim to remove the last redundant blank space System.out.println(newString.trim()); } }

java.lang.StringIndexOutOfBoundsException: String index out of range: -1 at java.lang.String.substring(String.java:1931) at com.codegym.task.task08.task0823.Solution.main(Solution.java:26) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeM

1) Please practice interpreting the error messages. The Java Virtual Machine send these messages with the purpose of to help you find the cause of the error. I quote a part of this error-message: "at com.codegym.task.task08.task0823.Solution.main (Solution.java:26)" This means that in the Solution class in the main method, look at line 26 well (in your new versioning program). I found this command there: String rest = w.substring (1); This is exactly the same mistake I described yesterday. You sent empty strings to the substring() method again, wich point to such an index what doesn't exist in an empty string. There were two lines in your program yesterday where you sent empty strings to the substring() method, which causes an error. There is already only one such line in it today. 2) I suggest to you, each of string variable before the loop would be better to have empty string, not a space. 3) If this command: newString += first.toUpperCase() + rest + " ";; is placed outside the (!w.isEmpty) condition block, then it will add the last valid value of the "first" variable to the earlier newString again and again, x times (x = (the number of the adjacent spaces in the input string)-1). This way: Sam Sam Sam Sam i i i i am So, in that case when (!w.isEmpty()) condition is false, it's better to do none action in the loop.

it's clear as a piece of ice! Thank you so much! I wish you good coding!:)

:)