StringBuilder trimToSize() method in Java with Examples

The trimToSize() method of StringBuilder class is the inbuilt method used to trims the capacity used for the character sequence of StringBuilder object. If the buffer used by StringBuilder object is larger than necessary to hold its current sequence of characters, then this method is called to resize the StringBuilder object for converting this object to more space-efficient. Calling this method may, but is not required to, affect the value returned by a subsequent call to the capacity() method.

Syntax:

public void trimToSize()

Returns: This method does not return anything.

Below programs illustrate the StringBuilder.trimToSize() method:

Example 1:

// Java program to demonstrate
// the trimToSize() Method.

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

        // create a StringBuilder object
        // with a String pass as parameter
        StringBuilder str
            = new StringBuilder("GeeksForGeeks");

        // add more string to StringBuilder
        str.append("Contribute");

        // print capacity
        System.out.println("Capacity before "
                           + "applying trimToSize() = "
                           + str.capacity());

        // applying trimToSize() Method
        str.trimToSize();

        // print string
        System.out.println("String = " + str.toString());

        // print capacity
        System.out.println("Capacity after"
                           + " applying trimToSize() = "
                           + str.capacity());
    }
}

Output:

Capacity before applying trimToSize() = 29
String = GeeksForGeeksContribute
Capacity after applying trimToSize() = 23

Example 2:

// Java program to demonstrate
// the trimToSize() Method.

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

        // create a StringBuilder object
        // with a String pass as parameter
        StringBuilder str
            = new StringBuilder();

        // add more string to StringBuilder
        str.append("GeeksForGeeks classes");

        // print capacity
        System.out.println("Capacity before"
                           + " applying trimToSize() = "
                           + str.capacity());

        // applying trimToSize() Method
        str.trimToSize();

        // print string
        System.out.println("String = " + str.toString());

        // print capacity
        System.out.println("Capacity after "
                           + "applying trimToSize() = "
                           + str.capacity());
    }
}

Output:

Capacity before applying trimToSize() = 34
String = GeeksForGeeks classes
Capacity after applying trimToSize() = 21

References:
https://docs.oracle.com/javase/10/docs/api/java/lang/StringBuilder.html#trimToSize()