In Java, parameterized methods are methods that accept parameters (or arguments) when they are called. This allows you to pass values into the method, which the method can then use for its processing. Parameterized methods enable you to write more flexible and reusable code, as they can operate on different data inputs.

Key Characteristics of Parameterized Methods:

1. Method Signature:

   • The method signature includes the method name and the types and order of its parameters. The parameters define what data types the method can accept when it is called.

2. Parameter Types:

   • A method can accept multiple parameters of different data types. You can also define methods with no parameters or with a variable number of parameters (using varargs).

3. Return Type:

   • A parameterized method can have a return type. It can return a value based on the parameters passed to it, or it can be a void method that does not return a value.

Example of Parameterized Methods

class Calculator {
    // Parameterized method to add two numbers
    int add(int a, int b) {
        return a + b;
    }

    // Parameterized method to multiply two numbers
    double multiply(double x, double y) {
        return x * y;
    }

    // Parameterized method to calculate the area of a rectangle
    double areaOfRectangle(double length, double width) {
        return length * width;
    }
}

// Main class to demonstrate parameterized methods
public class Main {
    public static void main(String[] args) {
        Calculator calc = new Calculator();

        // Calling parameterized methods with different arguments
        int sum = calc.add(5, 10);
        double product = calc.multiply(4.5, 2.0);
        double area = calc.areaOfRectangle(5.0, 3.0);

        // Displaying the results
        System.out.println("Sum: " + sum);                      // Output: Sum: 15
        System.out.println("Product: " + product);              // Output: Product: 9.0
        System.out.println("Area of Rectangle: " + area);       // Output: Area of Rectangle: 15.0
    }
}

Explanation:

• The Calculator class contains three parameterized methods:
  • add(int a, int b): Takes two integers and returns their sum.
  • multiply(double x, double y): Takes two doubles and returns their product.
  • areaOfRectangle(double length, double width): Takes two doubles representing the dimensions of a rectangle and returns its area.
• In the main method, an instance of Calculator is created, and the parameterized methods are called with different arguments.
• The results are printed to the console.

Advantages of Parameterized Methods:

1. Code Reusability:

   • By accepting parameters, a single method can perform operations on different inputs, promoting code reuse.

2. Flexibility:

   • Parameterized methods can handle various data inputs, making your code more adaptable to different scenarios.

3. Encapsulation:

   • Parameters allow you to pass information into methods without needing to rely on global variables, thereby maintaining encapsulation.

Summary:

• Parameterized methods in Java are methods that take input values (parameters) to perform operations.
• They enhance code flexibility, reusability, and encapsulation, allowing for cleaner and more maintainable code.
• By defining methods with parameters, you can create more dynamic and adaptable programs that can operate on various types of data.