Initialization is the next step. Here, for each type, we initialize a value to the variable. Think about placing a value inside the storage box:

score = 1000;
millisecondsElapsed = 1438165116841l;// 29th July 2016 11:19 am
subHorizontalPosition = 129.52f;
debugging = true;
playerName = "David Braben";

Notice that the String uses a pair of double quotes "" to initialize a value.

We can also combine the declaration and initialization steps. In the following we declare and initialize the same variables as we have previously, but in one step:

int score = 1000;
long millisecondsElapsed = 1438165116841l;//29th July 2016 11:19am
float subHorizontalPosition = 129.52f;
boolean debugging = true;
String playerName = "David Braben";

Whether we declare and initialize separately or together is dependent upon the specific situation. The important thing is that we must do both at some point:

int a;
// That's me declared and ready to go?
// The line below tries to output a to the console
Log.d("debugging", "a = " + a);
// Oh no I forgot to initialize a!!

This would cause the following warning:

There is a significant exception to this rule. Under certain circumstances, variables can have default values. We will see this in Chapter 8, Object-Oriented Programming; however, it is good practice to both declare and initialize variables.