JAVA-Structure - Notes By ShariqSP

Structure Of Java

The structure of Java programs is pivotal to understanding how Java code is organized and executed. At its core, a Java program consists of classes and methods.

Classes: In Java, a class is a blueprint for creating objects. It encapsulates data for the object and methods to operate on that data. For example:

                        
            public class MyClass {
                int myVariable;
            
                void myMethod() {
                    // Method implementation
                }
            }
                        
                    

Methods: Methods in Java are blocks of code that perform a specific task. They are defined within a class and can be called to perform the actions defined within them. For example:

                        
            public class MyClass {
                void myMethod() {
                    System.out.println("Hello, World!");
                }
            }
                        
                    

Understanding the structure of Java programs is essential for writing clean, efficient, and maintainable code. By organizing code into classes and methods, developers can create modular and reusable components, facilitating easier development and maintenance of Java applications.

Example:

                    
            package com.example;
            
            import java.util.Scanner;
            
            public class MyClass {
                // Static variables
                static int staticVar = 10;
                static {
                    // Static block
                    System.out.println("Static block: " + staticVar);
                    staticVar = 20;
                }
            
                // Non-static variables
                int nonStaticVar;
                {
                    // Non-static block
                    System.out.println("Non-static block: " + nonStaticVar);
                    nonStaticVar = 30;
                }
            
                // Constructor
                public MyClass() {
                    System.out.println("Constructor");
                }
            
                // Static method
                public static void staticMethod() {
                    System.out.println("Static method");
                }
            
                // Non-static method
                public void nonStaticMethod() {
                    System.out.println("Non-static method");
                }
            
                // Another method
                public void anotherMethod() {
                    System.out.println("Another method");
                }
            
                public static void main(String[] args) {
                    // Main method
                    System.out.println("Main method");
            
                    // Creating an instance of MyClass
                    MyClass obj = new MyClass();
            
                    // Calling methods
                    staticMethod();
                    obj.nonStaticMethod();
                    obj.anotherMethod();
                }
            }
                    
                

In this example, we have demonstrated the structure of a Java class, including package declaration, import statements, class declaration, static and non-static variables, static and non-static blocks, constructor, main method, and additional methods. The statements are arranged in the order of their execution within the class.