How to remove the last character of a string in Java

How to remove the last character of a string in Java:

Strings are immutable in Java. We can’t change or modify a string. If you do any modification to a string, it will create another string. For example, if you are adding a character to a string, it will create one more string object.

The characters of a string can be accessed by its index. The index starts from 0 and ends at length of the string - 1. i.e. the index of the first character is 0, of the second character is 1 etc.

Removing the last character of a string is removing the string length - 1th character.

In this post, I will show you two different ways to remove the last character of a string in Java.

Method 1: By using substring:

This is the easiest way to remove the last string character. Java String class provides a method called substring, by using which we can get a substring from a string.

This method is defined as like below:

public String substring(int start, int end)

Where, start and end are the start index and end index for the substring.

It creates a sub-string from start(inclusive) to end(exclusive) and returns that sub-string.
end is optional. If we don’t provide its value, it will pick to the end of the string.

But, remember that it might throw StringIndexOutOfBoundsException if:

The value of start is negative
If end is less than start
If start and end are greater than the length of the string.

We can use this method to remove the last character of a string. We have to pass the value of start as 0 and end as length of the string - 1. Since the value of end is exclusive, it will return one string excluding the last character.

The below program shows how to do that:

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        String str, str2;

        Scanner sc = new Scanner(System.in);

        System.out.println("Enter a string: ");
        str = sc.nextLine();

        str2 = str.substring(0, str.length() - 1);

        System.out.println("Original string: " + str);
        System.out.println("String removing last character: " + str2);
    }
}

In this program,

str and str2 are two String variables.
sc is a Scanner object to read the user input values.
It asks the user to enter a string. By using sc, it reads that string and put that in str.
It uses the substring method to find the required string. The start index is 0 and end index is length of the string - 1 passed to substring. It returns the new string by removing the last character and it is stored in str2.
The last two lines are used to print the original string and the newly created string.

If you run this program, it will print output as like below:

Enter a string: 
Hello World
Original string: Hello World
String removing last character: Hello Worl

Method 2: By converting the string to a StringBuilder object:

Another way to manipulate a string is by converting it to a StringBuilder object. StringBuilder has many advantages over strings. It doesn’t create any new object if we make any changes. We need to use the below method of StringBuilder:

public StringBuilder deleteCharAt(int i)

It takes one index value and delete the character at that index for the StringBuilder. We can call toString() method to convert a StringBuilder to string.

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        String str, str2;

        Scanner sc = new Scanner(System.in);

        System.out.println("Enter a string: ");
        str = sc.nextLine();

        str2 = new StringBuilder(str).deleteCharAt(str.length() - 1).toString();

        System.out.println("Original string: " + str);
        System.out.println("String removing last character: " + str2);
    }
}

Here, we are converting the string to a StringBuilder, deleting the last character and converting it back to a string.

It will give similar output:

Enter a string: 
Hello World
Original string: Hello World
String removing last character: Hello Worl

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How to remove the last character of a string in Java