Definition and declaration
The definition of a function specifies exactly how a function is constructed, what parameters are passed to it, and what value it returns to the calling function.
With the declaration we name a variable and make it known to the compiler.
Definition and declaration differ in some points. The definition includes a memory allocation for the methods, while no memory is allocated in the declaration. The declaration can be done several times, vice versa a method can be defined exactly once in a program.
Methods must be declared within a class in java. This gives the methods access to all variables of the object.
Syntax
modifiers return_type method_name(type parameter_1, type parameter_2, ...) {
// code to be executed
}Example
private void print() {
// code to be executed
}Another Example
Code Explanation
| Line | Description |
|---|---|
| 1 | Defines the method add() with the input parameters a and b of type integer. It’s a static, public method. Static methods can be called via a class and it is not necessary to create an object each time. A public method can also be called outside the class in which it was declared. The return value of the method is of type integer. |
| 2 | Creates a variable named result of type integer |
| 3 | Assigns the sum of a and b to the variable result |
| 4 | Returns the variable result |
public static int add(int a, int b) {
int result;
result = a + b;
return result;
}