Declaring variables
Description
Declaration gives a type and a name.
Explanation
Initialization assigns the first value.
Example
int score = 76;← Chapter 2 — Core Syntax & Data
6. Variables & Constants
mixed
Description
A variable is a named location that holds a value which may change. Declare its type before using it so Java knows what kind of data it should store.
A constant uses final and receives a value once. Constants make important fixed values, such as a passing score, visible and safer to reuse.
Subtopics
Using final
Description
A final variable cannot be reassigned.
Explanation
By convention, named constants use uppercase letters.
Example
final int PASSING_SCORE = 40;Explanation
Java requires local variables to be assigned before they are read. This protects you from accidentally using an unknown value.
Example
public class VariableDemo {
public static void main(String[] args) {
final int PASSING_SCORE = 40;
int score = 76;
System.out.println(score >= PASSING_SCORE);
}
}Key points
- Variables have a type and name.
- final prevents reassignment.
- Initialize local variables before reading them.