We have covered a lot of built-in functionality in Java throughout this lesson. We’ve seen +, -, <, ==, and many other operators. Most of these only work on primitives, but some work on Strings too!

Let’s say we want to print out a variable, and we want to describe it as we print it out. For our bank account example, imagine we want to tell the user:

Your username is: <username>

With the value of the variable username displayed.

The + operator, which we used for adding numbers together, can be used to concatenate Strings. In other words, we can use it to join two Strings together!

String username = "PrinceNelson";
System.out.println("Your username is: " + username);

This code will print:

Your username is: PrinceNelson

We can even use a primitive datatype as the second variable to concatenate, and Java will intelligently make it a String first:

int balance = 10000;
String message = "Your balance is: " + balance;
System.out.println(message);

This code will print:

Your balance is: 10000