Java String valueOf() example

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In this guide, you will learn about the String valueOf() method in Java programming and how to use it with an example.

1. String valueOf() Method Overview

Definition:

The valueOf() method of Java's String class returns the string representation of various data types, such as int, long, char, char array, float, double, boolean, and more. It's a static method that offers a simple way to convert primitives and certain objects to a string representation.

Syntax:

1. String.valueOf(data)

Parameters:

- data: This is the data to be converted into a string representation. It can be primitives (e.g., int, char) or objects.

Key Points:

- This method is overloaded to accommodate multiple data types.

- When given a null object reference, String.valueOf() returns the string "null" rather than throwing a NullPointerException.

- It’s commonly used for quick conversions of primitives and other basic data types to strings, especially when concatenating with other strings.

2. String valueOf() Method Example

public class ValueOfExample {
    public static void main(String[] args) {
        int intVal = 42;
        char[] charArray = {'H', 'e', 'l', 'l', 'o'};
        boolean boolVal = true;

        // Convert int to String
        String intString = String.valueOf(intVal);
        System.out.println("Integer as string: " + intString);

        // Convert char array to String
        String charArrayString = String.valueOf(charArray);
        System.out.println("Char array as string: " + charArrayString);

        // Convert boolean to String
        String boolString = String.valueOf(boolVal);
        System.out.println("Boolean as string: " + boolString);

        // Convert null object to String
        Object obj = null;
        String nullString = String.valueOf(obj);
        System.out.println("Null object as string: " + nullString);
    }
}

Output:

Integer as string: 42
Char array as string: Hello
Boolean as string: true
Null object as string: null

Explanation:

In the example:

1. The integer 42 is converted into the string "42".

2. The character array {'H', 'e', 'l', 'l', 'o'} is converted into the string "Hello".

3. The boolean true is converted into the string "true".

4. A null object reference is gracefully converted to the string "null" without any exceptions being thrown.

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