Creating Strings in Java

You may have noticed that you can combine strings with the + operator in Java, just as you can in JavaScript:

public class app
{
    public static void main(String[] args)
    {
        double chargesDue[][] = {{1093.66, 667.19, 45.99, 890.30, 99.06},
                                 {2019.00, 129.99, 19.01, 630.90, 23.17}};

        System.out.println("Customer 4 owes $" +
            chargesDue[0][4] + " in the eastern branch.");
        System.out.println("Customer 4 owes $" +
            chargesDue[1][4] + " in the western branch.");
    }
}

The reason this works is that strings are supported by the built-in class String in Java. In fact, the String class is treated in a special way in Java, and you can use it just as you would any built-in data type, as in the following case. (Note that I don't have to use the new operator or call the String class's constructor here.)

public class app
{
    public static void main(String[] args)
    {
        String welcome = "Welcome to Java";
        .
        .
        .

You can treat this new String variable as you would other simple variables, including printing it out like this:

public class app
{
    public static void main(String[] args)
    {
        String welcome = "Welcome to Java";

        System.out.println(welcome);
    }
}

In fact, there are really two string classes that are available in Java—the String and StringBuffer classes. String objects are read-only because they don't allow you to change their internal data. However, you can change the internal text in the StringBuffer class. Both these classes have many methods built into them, which you can find in the Java documentation.