StringBuffer delete() Method in Java with Examples

In Java, the StringBuffer class is used to create mutable sequences of characters. It allows modification of strings without creating new objects. One of the important methods provided by the StringBuffer class is the delete() method, which is used to remove a portion of characters from the string.

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

        StringBuffer sb = new StringBuffer("HelloWorld");
        sb.delete(5, 10);

        System.out.println(sb);
    }
}

Hello

Explanation: Original string: "HelloWorld", Characters from index 5 to 9 are removed. Remaining string becomes "Hello"

Syntax

public StringBuffer delete(int start, int end)

Parameters:

• start: Starting index (inclusive).
• end: Ending index (exclusive).

Return Value: Returns the same StringBuffer object after removing the specified substring.

Examples of Delete method

Example 1: Delete Characters from a Sentence

Deletes characters between index 5 and 9.

public class Geeks {
    public static void main(String[] args) {
        StringBuffer sbf = new StringBuffer("Welcome to Geeksforgeeks");
        System.out.println("StringBuffer = " + sbf);

        sbf.delete(5, 9);
        System.out.println("After deletion = " + sbf);
    }
}

StringBuffer = Welcome to Geeksforgeeks
After deletion = Welcoo Geeksforgeeks

Example 2: Negative Start Index

Passing a negative index causes an exception.

public class Geeks {
    public static void main(String[] args) {
        StringBuffer sbf = new StringBuffer("Welcome to Geeksforgeeks");
        sbf.delete(-5, 9);
    }
}

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: 
                                         String index out of range: -5
    at java.lang.AbstractStringBuilder.delete(AbstractStringBuilder.java:756)
    at java.lang.StringBuffer.delete(StringBuffer.java:430)
    at geeks.main(geeks.java:13)

Example 3: Index Beyond Length

Using indexes outside the valid range throws an exception.

public class Geeks {
    public static void main(String[] args) {
        StringBuffer sbf = new StringBuffer("Welcome to Geeksforgeeks");
        sbf.delete(99, 109);
    }
}