StringBuilder subSequence() in Java

subSequence(): This method is available in java.lang.AbstractStringBuilder class o Java.

Syntax:

CharSequence java.lang.AbstractStringBuilder.subSequence(int start, int end)

This method takes two arguments of type int as its parameters. This method returns a new character sequence that is a subsequence of this sequence.

Parameters: Two parameters are required for this method.

start: the start index, inclusive.

end: the end index, exclusive.

Returns: the specified subsequence.

Throws:

StringIndexOutOfBoundsException - if start or end is negative,if end is greater than length(),or if start is greater than end.

For Example:

StringBuilder str = new StringBuilder("Hello World")

int start = 3, end = 8

str.subSequence(start,end) = > It returns lo Wo.

Approach 1: When the index is in the range.

Java

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

        StringBuilder str = new StringBuilder("Hello World");

        int start = 3, end = 8;
        System.out.println(str.subSequence(start, end));
    }
}

Output:

lo Wo

Approach 2: When the index is out of range.

Java

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

        StringBuilder str = new StringBuilder("Hello World");

        int start = 10, end = 8;
        System.out.println(str.subSequence(start, end));
    }
}

Output:

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: start 10, end 8, length 11
	at java.base/java.lang.AbstractStringBuilder.checkRangeSIOOBE(AbstractStringBuilder.java:1802)
	at java.base/java.lang.AbstractStringBuilder.substring(AbstractStringBuilder.java:1066)
	at java.base/java.lang.StringBuilder.substring(StringBuilder.java:85)
	at java.base/java.lang.AbstractStringBuilder.subSequence(AbstractStringBuilder.java:1048)
	at java.base/java.lang.StringBuilder.subSequence(StringBuilder.java:85)