The codePointAt() method of the StringBuffer class is used to return the Unicode code point of the character at the specified index. If the character at the specified index is a high surrogate and the next character is a low surrogate, the method returns the Unicode code point represented by the surrogate pair.

• It supports Unicode characters represented using surrogate pairs.
• It throws IndexOutOfBoundsException if the index is invalid.+

public class GFG {
    public static void main(String[] args) {

        // Create a StringBuffer object
        StringBuffer str = new StringBuffer("Geeksforgeeks");

        // Get Unicode code point at index 10
        int codePoint = str.codePointAt(10);

        // Print the result
        System.out.println(
            "Unicode of Character at Index 10 = " + codePoint);
    }
}

Unicode of Character at Index 10 = 101

Explanation: The character at index 10 is e. Its Unicode code point is 101, so codePointAt(10) returns 101.

Syntax

public int codePointAt(int index)

• Parameters: index –> the index of the character whose Unicode code point is to be returned.
• Return Value: Returns the Unicode code point at the specified index.
• Exception: IndexOutOfBoundsException –> thrown if the index is negative or greater than or equal to length().

Example: To demonstrate IndexOutOfBoundsException

public class GFG {
    public static void main(String[] args) {

        // Create a StringBuffer object
        StringBuffer str =
            new StringBuffer("GeeksForGeeks Contribute");

        try {

            // Index 25 is outside the valid range
            int codePoint = str.codePointAt(25);

            System.out.println("Code Point: " + codePoint);
        }
        catch (IndexOutOfBoundsException e) {

            System.out.println("Exception: " + e);
        }
    }
}

Exception: java.lang.StringIndexOutOfBoundsException: Index 25 out of bounds for length 24

Explanation: The valid indexes range from 0 to length() - 1. Since index 25 is outside the valid range, codePointAt() throws an IndexOutOfBoundsException.

Advantages of codePointAt()

• Returns the Unicode code point of a character.
• Supports Unicode characters represented by surrogate pairs.
• Useful for working with Unicode text.
• Provides direct access to a character's code point using its index.
• Throws an exception for invalid indexes, helping identify incorrect access.