Java StringBuilder.codePointAt()

Java StringBuilder.codePointAt() – Examples

In this tutorial, we will learn about the Java StringBuilder.codePointAt() function, and learn how to use this function to get Unicode code point at specific index, with the help of examples.

codePointAt(int index)

StringBuilder.codePointAt() returns the character (Unicode code point) at the specified index.

The index has to be in the bounds of the StringBuilder length, else, you codePointAt() throws StringIndexOutOfBoundsException.

Syntax

The syntax of codePointAt() function is

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codePointAt(int index)

where

Parameter	Description
index	An integer representing the position of code point in the StringBuilder. index starts at 0.

Returns

The function returns, an integer, code point value at the specified index.

Example 1 – codePointAt()

In this example, we will create a StringBuilder object with some initial string literal. We will use codePointAt() to get Unicode code point at indexes 1 and 3, and print them.

Java Program

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public class Example { 
    public static void main(String[] args) { 
        // create a StringBuilder object 
        StringBuilder stringBuilder = new StringBuilder("abcdefgh"); 

        // get Unicode code point at index 1 
        int codePoint = stringBuilder.codePointAt(1); 
        System.out.println("Code Point at Index 1 is : "+ codePoint); 

        // get Unicode of char at position 3 
        codePoint = stringBuilder.codePointAt(3); 
        System.out.println("Code Point at Index 3 is : "+ codePoint);
    } 
}

Output

Code Point at Index 1 is : 98
Code Point at Index 3 is : 100

Example 2 – codePointAt() – Print All Code Points

In this example, we will print all the Unicode code points, by iterating over the sequence of StringBuilder.

Java Program

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public class Example { 
    public static void main(String[] args) { 
        // create a StringBuilder object 
        StringBuilder stringBuilder = new StringBuilder("abcdefgh"); 

        for(int i = 0; i < stringBuilder.length(); i++) {
        	System.out.println("Code Point at Index "+ i +" is : "+ stringBuilder.codePointAt(i));
        }
    } 
}

Output

Code Point at Index 0 is : 97
Code Point at Index 1 is : 98
Code Point at Index 2 is : 99
Code Point at Index 3 is : 100
Code Point at Index 4 is : 101
Code Point at Index 5 is : 102
Code Point at Index 6 is : 103
Code Point at Index 7 is : 104

Example 3 – codePointAt(int index) – StringIndexOutOfBoundsException

In this example, we will try to access Unicode code point at an index that is out of range for the StringBuilder.

Java Program

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public class Example { 
    public static void main(String[] args) { 
        // create a StringBuilder object 
        StringBuilder stringBuilder = new StringBuilder("abcdefgh"); 

        int index = 25;
        System.out.println(stringBuilder.codePointAt(index));
    } 
}

Output

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: index 25,length 8
	at java.base/java.lang.String.checkIndex(Unknown Source)
	at java.base/java.lang.AbstractStringBuilder.codePointAt(Unknown Source)
	at java.base/java.lang.StringBuilder.codePointAt(Unknown Source)
	at Example.main(Example.java:7)

Conclusion

In this Java Tutorial, we have learnt the syntax of Java StringBuilder.codePointAt() function, and also learnt how to use this function with the help of examples.

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Java StringBuilder.codePointAt() – Syntax & Examples