What is StringBuffer capacity() in Java?

The capacity() method of the StringBuffer class in Java is used to return buffer capacity. By default, a string buffer has a 16 character capacity. By calling this method, we can calculate its current capacity.

Capacity refers to the total number of character storage size in a string buffer.

Syntax

int capacity()

Parameters

N/A: It does not take any argument value.

Return Value

int: It returns the available size as integer count.

In Java, a primitive data-type integer is 32-bits. The range is from -2147483648 to 2147483647.

Example

The code below illustrates the use of the capacity() method of StringBuffer class. In line 7, sb1 is declared with a default size of 16. Whereas in line 11, sb2 is declared with a default value of "Welcome to". The total size will be 16+10=26.

// importing StringBuffer Class
import java.lang.StringBuffer;
// driver class
class EdPresso {
    // main method starting here
    public static void main( String args[] ) {
        StringBuffer sb1 = new StringBuffer();
        //printing default capacity of string buffer  
        System.out.println("sb1: default capacity: " + sb1.capacity()); 
        // current size 16+10 = 26
        StringBuffer sb2 = new StringBuffer("Welcome to");
        System.out.println("sb2: After declaration capacity: " + sb2.capacity()); 
        sb2.append(" Educative");
        // printing sb2 content
        System.out.println(sb2);
        // Againg printing sb2 content
        System.out.println("sb2:Current capacity after addition: " + sb2.capacity());      
    }
}