Variables and Types

Java is very precise. Before you tell it to remember something, you must tell it exactly what type it is.

And every sentence must end with a semicolon (;).

How Java remembers things

int number = 2026;
String welcome = "Hello, Java!";

Translation:

Remember one number (int) named number with the value 2026;
Remember one string (String) named welcome with the value "Hello, Java!";

What Java understands

There are only a few basic types the computer can remember.

int number = 10;            // integer
double decimal = 3.14;      // floating-point number
String text = "Hello";      // text
boolean truth = true;       // true or false

Use what you remembered

int x = 100;
System.out.println(x);

Think of it like this: when you ask Java to do something, you always say, “This is a number!” or “This is text!” first. And do not forget the ; at the end.