Java Program to Determine the Unicode Code Point at Given Index in String

Java's String class provides the codePointAt() method for this purpose. It returns the Unicode code point at the specified index. For characters represented by a single UTF-16 code unit, such as most English letters, the returned value corresponds to their Unicode value.

It returns the Unicode code point at the specified index.
The index is based on UTF-16 code units, not Unicode characters (code points).

Illustration:

String: G E E K S
Index: 0 1 2 3 4
|
Code: 71 69 69 75 83 , Output: 71
Input: str = "Geeks", index = 2
Output: 101

Syntax:

str.codePointAt(index);

Parameter: index – the index of the character whose Unicode code point is required.
Return Value: An int representing the Unicode code point at the specified index.

Java

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

        String str = "GEEKS";

        int result1 = str.codePointAt(0);
        int result2 = str.codePointAt(1);
        int result3 = str.codePointAt(2);
        int result4 = str.codePointAt(3);
        int result5 = str.codePointAt(4);

        System.out.println("Original String: " + str);

        System.out.println("Unicode code point at index 0 = "
                           + result1);
        System.out.println("Unicode code point at index 1 = "
                           + result2);
        System.out.println("Unicode code point at index 2 = "
                           + result3);
        System.out.println("Unicode code point at index 3 = "
                           + result4);
        System.out.println("Unicode code point at index 4 = "
                           + result5);
    }
}

Output

Original String: GEEKS
Unicode code point at index 0 = 71
Unicode code point at index 1 = 69
Unicode code point at index 2 = 69
Unicode code point at index 3 = 75
Unicode code point at index 4 = 83

Explanation:

The string "GEEKS" is stored in the str variable.
codePointAt() is called with different indexes.
Each call returns the Unicode code point at that index.
The returned value is stored in an int variable.
For example, str.codePointAt(0) returns 71, the Unicode code point of 'G'.

Example: Handling an Invalid Index

If the specified index is negative or greater than or equal to the string's length, codePointAt() throws a StringIndexOutOfBoundsException.

Java

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

        String str = "Geeksforgeeks";

        try {
            int result1 = str.codePointAt(0);
            int result2 = str.codePointAt(-4);

            System.out.println("Unicode code point at index 0 = "
                               + result1);
            System.out.println("Unicode code point at index -4 = "
                               + result2);
        }
        catch (StringIndexOutOfBoundsException e) {
            System.out.println("Exception: " + e.getMessage());
        }
    }
}

Output

Exception: Index -4 out of bounds for length 13

Explanation

str.codePointAt(0) is valid because 0 is a valid index.
str.codePointAt(-4) is invalid because string indexes cannot be negative.
Therefore, StringIndexOutOfBoundsException is thrown.
The try-catch block handles the exception and prevents abnormal program termination.

Java Program to Determine the Unicode Code Point at Given Index in String

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