Java String toString() method
Syntax and Examples

Syntax

public String toString()

Parameters

Return Value

Examples

Example 1: Default Implementation

This example demonstrates using the default implementation of toString() for String objects. When you don't override this method, it returns a string that represents the class name and the object’s hash code.

public class DefaultToString {
    public static void main(String[] args) {
        String str = "Hello World";
        System.out.println(str.toString());
    }
} 

Hello World

In this case, the default implementation of `String`'s toString() method is called which simply returns the String itself. Therefore, printing the result gives us "Hello World".

Example 2: Overriding toString() in a Custom Class

This example shows how to override the toString() method in a custom class that uses a String internally. This allows you to control how objects of your class are represented as strings.

class Person {
    private String name;

    public Person(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "Person [name="+name+ "]";
    }

    public static void main(String[] args) {
        Person person = new Person("Alice");
        System.out.println(person.toString());
    }
}

Person [name=Alice]

Here, the toString() method is overridden in the Person class. Instead of returning a generic representation, it returns a string that includes the person's name within square brackets. This customized output makes debugging and logging much easier.

Example 3: toString() with StringBuilder

This example shows using toString() on a `StringBuilder` object. `StringBuilder` is mutable, while String is immutable. When you need to manipulate strings frequently, `StringBuilder` offers better performance.

    public class StringBuilderToString {
    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder();
        sb.append("This is a ");
        sb.append("StringBuilder.");

        System.out.println(sb.toString());
    }
}

This is a StringBuilder.

The toString() method on the `StringBuilder` object converts its internal character sequence into an immutable String object, which can then be printed to the console.