Java String valueOf() example

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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