Index of a sample string in a string

I am sure many of us who write codes in Java use the method indexOf() to get the index of a string in a given string. I use this method quite frequently too and I thought of writing a method that replicates the functionality of indexOf() that is readily available in the Java SDK. In addition to that, I thought this could be an exciting thing to do - dissecting and reverse engineering Java API methods.

Well, I wrote this code and would like to share with the readers of this blog. I hope you find it useful. Please feel free to drop a line if you have a better way to solve this problem. The code is quite self explanatory. It mainly reads through the original string and while reading it, the sample string is being compared.

 
// To get the index of the first occurrence of a matching substring
public static int indexOf(String inputString, String sampleString){
  // set the length of input string
  int length = inputString.length();
  int inputStringIndex = -1;
  StringBuffer newString = new StringBuffer();
  // to keep track of current index of character of input string
  int index = 0;
  // to keep track of current index of character of sample string
  int check = 0;
  while (index < length) {
    try {
      if (inputString.charAt(index) == sampleString.charAt(check)) {
        newString.append(inputString.charAt(index));
        check++;
        if (newString.toString().equals(sampleString)) {
        /**
          * set the index of the first occurrence of the 
          * matching substring
          */
          inputStringIndex = (index - check) + 1 ;
          break;
        }
      }
    } catch (Exception ex){} 
    index++;
  }  
  return inputStringIndex;
}