Method Types in Java

Types of Methods in Java

• Predefined/Standard Library Methods: These methods are built into the Java language and are available through the Java Class Library (API). You don't need to write them, just call them. Examples include System.out.println(), Math.max(), and String.length().
• User-Defined Methods: These are methods created by the programmer to perform custom tasks specific to their application.

This is the most important distinction for user-defined methods.

• Instance Methods:
  • Belong to an instance (object) of a class.
  • Must be called on a specific object.
  • Can access both instance variables and static variables of the class.
  • Example:

    class Dog {
        String name;
        public void bark() { // Instance method
            System.out.println(name + " says Woof!");
        }
    }
    Dog myDog = new Dog();
    myDog.name = "Buddy";
    myDog.bark(); // Called on the `myDog` object.
                            

• Static Methods:
  • Belong to the class itself, not any individual object.
  • Called using the class name.
  • Cannot access instance variables directly (as they belong to objects). They can only access static variables.
  • Example:

    class Calculator {
        public static int add(int a, int b) { // Static method
            return a + b;
        }
    }
    int sum = Calculator.add(5, 10); // Called on the `Calculator` class.