StringBuffer codePointAt() method in Java with Examples

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.