Easy question about parts of this code

Question

Code: The purpose is to find a character in a string, and report how many times the character occurs in the string. Basically the program does looking and counting. The code is complied and working well, but my goal is to make it as short as possible, if you can just write a program does the same job in no more than five lines, i will be very appreciate if you share your idea with me.
public class CharFinder{
public static void main(String args[])throws java.io.IOException{
String content;
char target;
int fromIndex = 0;
int foundIndex;
int count = 0;
content =("hello world, i am a boy, and i need help.");
System.out.print("Enter the character to be counted: ");
target = (char)System.in.read();
for (int i=0;i<=content.length()-1;i++)
foundIndex = content.indexOf(target, fromIndex);
if (foundIndex >= 0)
count++;
fromIndex = foundIndex + 1;
System.out.println(" '" + target + "' occurs " + count + " time(s)");
Question:
1.what does string.indexOf do?
2. what are fromIndex and foundIndex 's jobs in the code? in another word, what are they doing in the code?
3. I have to put it in a method, like public void charFinder(), but it cannot compile cuz of throws java.io.IOException, the compiler always says it needs ; at the end..........i can't understand the problem.
Thank you so much if you can answer them.

Answer 1

I think the from index counts how many letters are from the index... and the found are the letters that were found, and the +1 tells it to go on to the next letter to see if it should send that letter back to you.... your third question, the compilers always say you need stuff, adn when you find a problem it has ntohing to do with what it says... my suggestion is just look for something that might be out of place.