String stringName = "Hello";
String characterToFind = "l";
//This example will find all the Ls in this string and will print the index of
//it as soon as it is detected

for(int i = 0; i < stringName.length(); i++){
  if(stringName.substring(i, i+1).equals(characterToFind)){
    System.out.println(characterToFind + "found at " + i);
  }
  
}

int index = word.indexOf(guess);
while (index >= 0) {
    System.out.println(index);
    index = word.indexOf(guess, index + 1);
}