StringBuilder sb = new StringBuilder("Hello World"); char firstChar = sb.charAt(0); System.out.println(firstChar); // Output: H
StringBuilder sb = new StringBuilder("Hello World"); for (int i = 0; i < sb.length(); i++) { char ch = sb.charAt(i); System.out.print(ch + " "); } // Output: H e l l o W o r l dThe StringBuilder class belongs to the java.lang package, which means that it is part of the core Java library.