java - How to find the first character of a String without using any API method -

recently being asked question in interview:

find first character of string without using method string class

gave following approaches, assuming str string:

1. str.charat(0)
2. str.tochararray()[0]
3. str.substring(0,1)

can suggest me way can achieved?

using matcher api (and not string): create pattern captures every character find first 1 , print (the dotall mode enabled handle case first character line separator).

public static void main(string[] args) {     matcher matcher = pattern.compile("(.)", pattern.dotall).matcher("foobar");     if (matcher.find()) {         system.out.println(matcher.group(1)); // prints "f"     } }