Socket communication in Java enables communication between two endpoints over a network. There are two main types of sockets: TCP sockets and UDP sockets. Let's explain both types with examples: TCP Socket Communication: 1. **Server Side**: - The server creates a `ServerSocket` object to listen for incoming connections on a specific port. - When a client connects, the server accepts the connection and creates a `Socket` object to communicate with the client. - The server reads from and writes to the socket's input and output streams to communicate with the client. import java.io.*; import java.net.*; public class TCPServer { public static void main(String[] args) throws IOException { ServerSocket serverSocket = new ServerSocket(12345); System.out.println("Server started. Waiting for client..."); Socket clientSocket = serverSocket.accept(); System.out.println("Client connected."); BufferedReader in = new Bu
Class, Object, Object Reference, Method, and Constructor in Java
Class:
In Java, a class is a blueprint or template that defines the structure and behavior of objects. It acts as a template for creating objects, encapsulating data (attributes) and methods (functions) that operate on that data.
Syntax:
public class ClassName {
// Attributes
dataType attributeName;
// Constructor
public ClassName(parameters) {
// Initialization code
}
// Methods
returnType methodName(parameters) {
// Method body
}
}
Object:
An object is an instance of a class. It is a concrete realization of the class blueprint, possessing its own unique state (attributes) and behavior (methods). Objects represent real-world entities and are created based on the class template.
Object Creation:
ClassName objectName = new ClassName(arguments);
Method:
A method is a function defined within a class that performs a specific task or action. It represents the behavior associated with the class. Methods are called on objects to manipulate their data or perform certain operations.
### Syntax:
returnType methodName(parameters) {
// Method body
}
Object Reference:
An object reference is a variable that stores the memory address of an object. When you create an object, you use the new keyword, and an object reference is assigned to the created object. This reference is used to access and manipulate the object.
Example:
ClassName obj1 = new ClassName(arguments);
ClassName obj2 = obj1; // obj2 now references the same object as obj1
Constructor:
A constructor is a special method with the same name as the class, used to initialize the attributes of an object when it is created. It is called automatically when an object is instantiated.
Syntax:
public ClassName(parameters) {
// Initialization code
}
Example:
public class Car {
// Attributes
String make;
String model;
int year;
// Constructor
public Car(String make, String model, int year) {
this.make = make;
this.model = model;
this.year = year;
}
// Method
void displayInfo() {
System.out.println("Make: " + make);
System.out.println("Model: " + model);
System.out.println("Year: " + year);
}
}
Object Creation and Method Invocation:
// Creating an Object
Car myCar = new Car("Toyota", "Camry", 2022);
// Accessing Attributes
String carMake = myCar.make;
int carYear = myCar.year;
// Invoking Method
myCar.displayInfo();
Understanding classes, objects, methods, and constructors is essential for effective object-oriented programming in Java. These concepts provide a structured way to model and interact with real-world entities in software development.
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