How to Call a Method in Java

Methods are essential in Java programming as they promote code reusability, modularity, abstraction, and structure, making the code more efficient and maintainable. This guide aims to provide a comprehensive understanding of calling methods in Java. We’ll start with the basics, exploring the process of calling static methods, followed by the convenience of invoking pre-defined methods. Moving forward, we’ll delve into the intricacies of calling user-defined methods, and finally, demystify the procedures involved in calling abstract methods. By the end of this guide, you’ll have a solid grasp of various method calling techniques, empowering you in your Java programming journey. Let’s dive into the details of Java method calls! ?

Calling Static Method in Java

In Java programming, the process of calling static methods is straightforward yet powerful. Static methods, associated with the class rather than instances, provide accessibility without requiring object creation. Let’s illustrate this with a simple example:

public class StaticMethodExample {
    // A static method
    public static void greet() {
        System.out.println("Hello from the static method!");
    }

    public static void main(String[] args) {
        // Calling the static method without creating an object
        greet();
    }
}

In this example, the StaticMethodExample class features a static method named greet. To call this method, we directly invoke it using the class name and the dot operator: StaticMethodExample.greet();

Executing this Java program produces the following output:

Hello from the static method!

Understand and implementing the simplicity of calling static methods establishes a strong foundation for further Java programming. As we explore further, you’ll discover additional approaches to enhance your coding skills. Stay tuned for the next segment on calling pre-defined methods!

Tips: What is the main difference between static and non-static methods in Java?

In Java, the key distinction between static and non-static (instance) methods lies in their association with the class and instances, respectively.

  • Static methods belong to the class rather than instances of the class. They can be called directly using the class name, and they are often used for utility functions or operations that don’t require instance-specific data.
  • Non-static methods are associated with instances of the class. They operate on the specific attributes and behaviors of an object and are called using an object of the class.

Calling the Pre-Defined Method in Java

Pre-defined methods in Java are methods that are provided by the Java language itself or by built-in libraries. These methods are already implemented and available for use without the need to write the code for them from scratch. They provide various functionalities for performing common operations.

To call a pre-defined method in Java, follow these steps:

  1. Identify the class or library that provides the pre-defined method. This could be a built-in class like Math or a library class like ArrayList.
  2. If the method is a static method, use the class name followed by a dot (.) operator to access the method.
ClassName.methodName();

If the method is a non-static method, create an object of the class and use the dot (.) operator to access the method.

ClassName objectName = new ClassName();
objectName.methodName();
  1. If the method requires any arguments, provide them within the parentheses following the method name.
ClassName.methodName(argument1, argument2);

Here’s an example of calling a pre-defined method:

public class Main {
public static void main(String[] args) {
int number = 5;

// Using a pre-defined method from the Math class
double squareRoot = Math.sqrt(number);
System.out.println(Square root of + number + is: + squareRoot);

// Using a pre-defined method from the String class
String text = Hello, World!;
int length = text.length();
System.out.println(Length of the string is: + length);
}
}

Output:

Square root of 5 is: 2.23606797749979
Length of the string is: 13

By using pre-defined methods, you can leverage existing functionality and save time by not having to implement the same logic yourself. These methods are a crucial part of the Java language and its libraries, providing a wide range of functionality for various tasks.

Calling User-Defined Method in Java

To call a user-defined method in Java, you need to follow these steps:

  1. Define the method within a class. The method can be static or non-static, depending on your requirements.
  2. If the method is non-static, create an object of the class that contains the method. If the method is static, you can skip this step.
  3. Use the object (if applicable) or class name (for static methods) followed by a dot (.) operator to access the method.
  4. If the method requires any arguments, provide them within the parentheses following the method name.

Here’s an example of calling a user-defined method:

class ExampleClass {
public void printMessage() {
System.out.println(This is a user-defined method);
}

public int addNumbers(int a, int b) {
return a + b;
}
}

public class Main {
public static void main(String[] args) {
ExampleClass obj = new ExampleClass(); // Creating an object

// Calling a non-static method
obj.printMessage();

// Calling a non-static method with arguments
int sum = obj.addNumbers(5, 3);
System.out.println(Sum of numbers: + sum);

// Calling a static method without an object
ExampleClass.staticMethod();
}
}

Output:

This is a user-defined method
Sum of numbers: 8

Note that for non-static methods, you need to create an object of the class using the new keyword before calling the method. For static methods, you can call them directly using the class name. User-defined methods allow you to modularize your code and perform specific tasks, making your program more organized and easier to maintain.

Calling Abstract Method in Java

In Java, an abstract method is a method declared without an implementation. It is only defined in an abstract class or interface and lacks a body, meaning it does not provide any specific implementation details. Abstract methods are meant to be overridden by subclasses or implemented by classes that implement the interface.

Here are some key points about abstract methods:

  1. Declaration: To declare an abstract method, the abstract keyword is used before the method declaration, and it ends with a semicolon (;) instead of a body.
  2. Abstract Class or Interface: Abstract methods can only exist in abstract classes or interfaces. An abstract class is a class that cannot be instantiated and can contain abstract methods and non-abstract methods. An interface is a collection of abstract methods.
  3. Subclass Implementation: Any subclass extending an abstract class or implementing an interface that contains abstract methods must provide an implementation for those abstract methods. Failure to provide an implementation will result in a compilation error.
  4. Calling Abstract Methods: Abstract methods cannot be called directly. They need to be overridden by a concrete subclass or implemented by a class implementing the interface. You can, however, call the overridden/implemented method on an instance of the subclass or implementing class.

Here’s an example of an abstract class with an abstract method:

“`java
abstract class Animal {
public abstract void sound(); // Abstract method declaration

public void sleep() {

More example

To call a method in Java, you need to follow these steps:

  1. Create an object of the class that contains the method you want to call. If the method is a static method, you can skip this step.
ClassName objectName = new ClassName();
  1. Use the dot (.) operator to access the method from the object created in the previous step.
objectName.methodName();
  1. If the method requires any arguments, provide them within the parentheses following the method name.
objectName.methodName(argument1, argument2);

Here’s an example:

// Define a class with a method
class ExampleClass {
public void helloWorld() {
System.out.println(Hello, World!);
}
}

// Create an object and call the method
public class Main {
public static void main(String[] args) {
ExampleClass obj = new ExampleClass();
obj.helloWorld();
}
}

Output:

Hello, World!

Note: If the method is a static method, you can directly call it using the class name instead of creating an object.

ClassName.methodName();

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