ValueOf

This static method converts a value (like an int or boolean) into a String. We do not call it on a String instance—instead we use the String class itself.

A static method, we use valueOf to get string representations of things. For example contain the int 100. This is not a string. With valueOf we get "100."

An example

Let's try the String.valueOf method. Here we use it with an int argument and then a boolean argument (100 and false). It returns a string after each call.

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

        // Convert 100 to a String and test it.
        String value = String.valueOf(100);
        if (value.equals("100")) {
            System.out.println(true);
        }

        // Convert "false" to a String.
        String literal = String.valueOf(false);
        if (literal.equals("false")) {
            System.out.println(true);
        }
    }
}
true
true

CopyValueOf

This method receives a char array and returns a string with the same characters. It can take an offset and a count, or convert the entire array.

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

        char[] letters = { 'a', 'b', 'c' };

        // Use copyValueOf to convert char array to String.
        String result = String.copyValueOf(letters);
        System.out.println(result);
    }
}
abc

Some notes, valueOf

For things like ints and booleans, we cannot use a toString method. These are not objects—they are values. So we have to use the static String.valueOf method.

Some notes, syntactic sugar

For beautiful-looking programs, we need beautiful syntax. But the String.valueOf method is not often needed—instead, we prefer real objects in Java.