Java StringBuilder setLength() method

The setLength(int newLength) method of StringBuilder class is used to set the new length of the character sequence. The new length of character sequence becomes to specified newLength argument.

If the newLength argument is less than the current length, the new length of character sequence will change to newLength. On the other hand, if the newLength argument is greater than the current length then the null character(s) '\u0000' are appended so that length becomes the newLength argument.

Syntax:

Parameter:

DataType	Parameter	Description
int	newLength	It is a new length of character sequence.

Returns:

Exception:

IndexOutOfBoundsException - if the newLength argument is negative.

Compatibility Version:

Java 1.5 and above

Example 1

public class StringBuilderSetLengthExample1 {
	public static void main(String[] args) {
		StringBuilder sb = new StringBuilder("stringbuilder");
		System.out.println("string: "+sb);
		System.out.println("length: "+sb.length());
		//set new length of character sequence
		sb.setLength(6);
		System.out.println("set new length: "+sb.length());
		System.out.println("new sequence: "+sb);
	}
}

Test it Now

Output:

string: stringbuilder
length: 13
set new length: 6
new sequence: string

Example 2

public class StringBuilderSetLengthExample2 {
	public static void main(String[] args) {
		StringBuilder sb = new StringBuilder("stringbuilder");
		System.out.println("string: "+sb);
		System.out.println("length: "+sb.length());
		//set new length of character sequence
		sb.setLength(20);
		System.out.println("set new length: "+sb.length());
		System.out.println("new sequence: "+sb);
	}
}

Test it Now

Output:

string: stringbuilder
length: 13
set new length: 20
new sequence: stringbuilder

Example 3

public class StringBuilderSetLengthExample3 {
	public static void main(String[] args) {
		StringBuilder sb = new StringBuilder("stringbuilder");
		System.out.println("string: "+sb);
		System.out.println("length: "+sb.length());
		//set new length of character sequence
		sb.setLength(-1);
		System.out.println("set new length: "+sb.length());
		System.out.println("new sequence: "+sb);
	}
}

Test it Now

Output:

string: stringbuilder
length: 13
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: -1
	at java.lang.AbstractStringBuilder.setLength(Unknown Source)
	at java.lang.StringBuilder.setLength(Unknown Source)
	at snippet.StringBuilderSetLengthExample3.main(StringBuilderSetLengthExample3.java:7)

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