How to use the substring and can i class method for the primitive type

Question

MY COMPILER
public class StringLine
public static void main(String[] args)
String sentence;
char letter;
char name;
int position;
System.out.println("Enter a line of text. No punctuation please");
sentence = MyIO.readLine();
System.out.println("I have rephrase that line to read:");
position = sentence.indexOf(" ");
name = sentence.charAt(postion, position+ 1);
name = name.toUpperCase();
letter = sentence.charAt(0);
letter = letter.toLowerCase();
sentence = name + sentence.substring(position + 2)
          + letter + sentence.substring(1, position);
//////////////// I got 3 errors following:
StringLine.java:16: cannot resolve symbol
symbol : variable postion
location: class StringLine
name = sentence.charAt(postion, position+ 1);
^
StringLine.java:17: char cannot be dereferenced
name = name.toUpperCase();
^
StringLine.java:20: char cannot be dereferenced
letter = letter.toLowerCase();
^
3 errors
}

Answer 1

position = sentence.indexOf(" ");
name = sentence.charAt(postion, position+ 1);
name = name.toUpperCase(); two error here:
1. as stated above postion is mispelled...should be position
2. you cannot perform a chatAT(int, int)
I think you want to perform a substring
String name;  // should be a string instead of a char..(char is a primitive and all primitive have no method)
position = sentence.indexOf(" ");  
name = sentence.substring(position, position + 1).toUpperCase();
[./code]
better yet..you should check if the sentence does contain a spaceString name;
position = sentence.indexOf(" "); // return a negative value if the search string is not part of the string
if (position != -1)
name = sentence.substring(position, position + 1).toUpperCase();
else
System.out.println("The sentence does not contain a space);
[./code]
String letter;
letter = new String(sentence.charAt(0));
letter = letter.toLowerCase();
// or
char letter;
letter = sentence.toLowercase().charAt(0);