Java StringBuilder length example (StringBuffer length)

StringBuilder length example shows how to get the StringBuilder object’s length or size using the length method. Since the StringBuilder class is a drop-in replacement for the StringBuffer class, the example works for StringBuffer too.

How to get the StringBuilder length using the length method?

The length method of the StringBuilder or StringBuffer class returns the number of characters stored in the StringBuilder or StringBuffer object.

1	public int length()

In other words, it returns the character count of the StringBuilder.

StringBuilder length example

public class StringBuilderLengthExample {

public static void main(String[] args) {

StringBuilder sbld = new StringBuilder("Hello");

* To get the StringBuilder size, use the length method

int size = sbld.length();

System.out.println("StringBuilder content: " + sbld);

System.out.println("Length is: " + size);

* The size changes as and when we add more

* contents to the StringBuilder or StringBuffer object

sbld.append("world");

size = sbld.length();

System.out.println("StringBuilder content: " + sbld);

System.out.println("Length is: " + size);

}

Output

StringBuilder content: Hello

Length is: 5

StringBuilder content: Helloworld

Length is: 10

When we first create an empty StringBuilder, the length method returns 0 as there are no characters in it.

How to check if StringBuilder is empty using the length method?

The length method returns 0 if there are no characters in the StringBuilder or StringBuffer object. We can compare the return value of the length method with 0 to check if the StringBuilder is empty or not.

StringBuilder sbld = new StringBuilder("");

if(sbld.length() == 0)

System.out.println("StringBuilder is empty");

else

System.out.println("StringBuilder is not empty");

* Or use a shortcut!

System.out.println("Is StringBuilder empty? " + (sbld.length() == 0) );

Output

1 2	StringBuilder is empty Is StringBuilder empty? true

How to iterate StringBuilder contents using the length method?

We can also iterate over the characters of the StringBuilder or StringBuffer object using for loop as given below.

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

for(int i = 0 ; i < sbld.length() ; i++){

System.out.println( sbld.charAt(i) );

}

Output

This example is a part of the Java StringBuffer tutorial and Java StringBuilder tutorial.

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Rahim

I have a master's degree in computer science and over 18 years of experience designing and developing Java applications. I have worked with many fortune 500 companies as an eCommerce Architect. Follow me on LinkedIn and Facebook.