Java Overview
Java is a high-level, class-based, object-oriented programming language designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let application developers write once, run anywhere (WORA).
Key Features
- Platform Independent: Java code is compiled into bytecode that runs on any JVM.
- Object-Oriented: Follows OOP concepts like inheritance, encapsulation, polymorphism.
- Robust: Strong memory management, exception handling, and type checking.
- Secure: Provides security features like bytecode verification, sandboxing.
- Multithreaded: Supports concurrent programming with built-in thread support.
- High Performance: Just-In-Time (JIT) compilers enable high performance.
- Rich Standard Library: Comprehensive collection of utilities and APIs.
Common Use Cases
Enterprise Applications
Java EE is widely used for large-scale business applications.
Android Development
Primary language for native Android app development.
Web Applications
Used with frameworks like Spring and Jakarta EE.
Big Data Technologies
Hadoop, Spark, and other big data tools are written in Java.
Example Code
// Simple Java program demonstrating OOP concepts
public class Main {
public static void main(String[] args) {
// Create a Person object
Person person = new Person("Alice", 30);
person.greet();
// Demonstrate polymorphism
Animal myAnimal = new Dog();
myAnimal.makeSound();
}
}
class Person {
private String name;
private int age;
public Person(String name, int age) {
this.name = name;
this.age = age;
}
public void greet() {
System.out.println("Hello, my name is " + name);
}
}
abstract class Animal {
abstract void makeSound();
}
class Dog extends Animal {
@Override
void makeSound() {
System.out.println("Woof!");
}
}