Java - replace last n characters in string

In this article, we would like to show you how to replace last n characters in string in Java.

Quick solution:

String text = "ABCD";
int n = 3;
String replacement = "123";
String result = text.substring(0, text.length() - n) + replacement;

System.out.println(result);  // A123

Practical example

In this example, we use substring() method to remove last n = 3 characters from the text string, then we add the replacement at their place.

public class Example {

    public static void main(String[] args) {
        String text = "ABCD";
        int n = 3;
        String replacement = "123";
        String result = text.substring(0, text.length() - n) + replacement;

        System.out.println("Original string: " + text);     // ABCD
        System.out.println("Modified string: " + result);   // A123
    }
}

Output:

Original string: ABCD
Modified string: A123

Note:

The replacement length doesn't have to be equal to n. You can remove the last n characters from the end of the string and add any number of characters instead.