Let’s delve into methods in Java
In Java, the definition of a method is composed of two parts:
- The definition, which defines its interface.
- The block, formed by the commands that implement its behavior.
It is not allowed to declare methods within other methods (to the version)
Method definition
The setting of a method can be of two types, depending on whether or not the method can return a value:
- Methods with return: the setting must specify the type of value returned.
- Methods without return: the setting must use the keyword
void.
The parameters in the setting constitute the formal parameters of the method.
Method call
A method is activated by making its call. The call must provide the values to be associated with the formal parameters.
Static methods and dynamic methods
A static method is executable from the class in which it is defined. A dynamic method is executable by objects that are instantiable from its definition class.
Constructor methods
Constructor methods are special methods that are used to instantiate objects. Constructor methods have the following properties:
- They are public.
- They have the same name as the class.
- They do not have a return type.
Example
```java class Person { public int age;
public Person(int age) {
this.age = age;
}
public int getAge() {
return age;
} }
public class Main { public static void main(String[] args) { Person person = new Person(20);
// Method with return
int age = person.getAge();
System.out.println("The person's age is: " + age);
// Method without return
person.changeAge(30);
System.out.println("The person's age is now: " + person.age);
} }
Notes
- A method with return must always return a value. If it is not necessary to return any value, you can use the keyword
void. - A static method can be called without creating an object of the class in which it is defined.
- A dynamic method can only be called after creating an object of the class in which it is defined.