Defining & calling methods

Return types, parameters, the return statement, and void.

Methods: named, reusable code

A method has a return type, a name, a parameter list, and a body. Use void when nothing is returned:

// returns an int
public static int add(int a, int b) {
    return a + b;
}

// returns nothing
public static void greet(String name) {
    System.out.println("Hello, " + name);
}

// calling:
int result = add(3, 4);   // 7
greet("Ada");              // Hello, Ada

Key rules: - Every non-void method must have a return on every reachable path — the compiler checks this ("missing return statement" is a compile error). - A void method may have return; (with no value) to exit early. - Arguments are matched to parameters by position, not name. - Java is strictly typed — you cannot pass the wrong type without an explicit cast.