public class StringMethodsExample {
    public static void main(String[] args) {
        String str = "Hello, World!";

        // Length of the string
        int length = str.length();
        System.out.println("Length of the string: " + length);

        // Concatenation
        String newStr = str.concat(" How are you?");
        System.out.println("Concatenated string: " + newStr);

        // Substring
        String substring = str.substring(7);
        System.out.println("Substring from index 7: " + substring);

        // Character at a specific index
        char charAtIndex = str.charAt(0);
        System.out.println("Character at index 0: " + charAtIndex);

        // Index of a specific character
        int indexOfComma = str.indexOf(",");
        System.out.println("Index of comma: " + indexOfComma);

        // Conversion to lowercase and uppercase
        String lowercase = str.toLowerCase();
        String uppercase = str.toUpperCase();
        System.out.println("Lowercase: " + lowercase);
        System.out.println("Uppercase: " + uppercase);

        // Checking for presence of a substring
        boolean containsHello = str.contains("Hello");
        System.out.println("Contains 'Hello': " + containsHello);

        // Removing leading and trailing whitespaces
        String stringWithSpaces = "   Trim me   ";
        String trimmedString = stringWithSpaces.trim();
        System.out.println("Trimmed string: " + trimmedString);
    }
}