Java Programming Overview

Java is a high-level, object-oriented, platform-independent programming language.

1. Introduction to Java

"Hello, World!" program demonstrates Java basics.

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

2. Setup Java Environment

Install JDK, set JAVA_HOME, and use javac and java commands.

3. Operators and Expressions

Arithmetic operations using Java operators.

int result = 5 + 3; // Output: 8

4. String Class and Printing

Manipulate and display strings.

String message = "Hello, Java!";
System.out.println(message.toUpperCase());

5. Conditional Statements

Control program flow with if-else.

int number = 10;
if (number > 0) {
    System.out.println("Positive");
} else {
    System.out.println("Negative");
}

6. Loops

Iterate with loops.

for (int i = 1; i <= 5; i++) {
    System.out.println(i);
}

7. Arrays

Work with collections of elements.

int[] numbers = {1, 2, 3, 4};
System.out.println(numbers[0]); // Output: 1

8. Methods and Packages

Encapsulate code in reusable methods.

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

9. Exception Handling

Handle runtime errors gracefully.

try {
    int result = 10 / 0;
} catch (ArithmeticException e) {
    System.out.println("Cannot divide by zero");
}

10. Multithreading

Run parallel threads.

class MyThread extends Thread {
    public void run() {
        System.out.println("Thread running");
    }
}
new MyThread().start();

11. java.lang Package

Use fundamental Java classes.

String str = "123";
int num = Integer.parseInt(str);
System.out.println(num);

12. Annotations and Javadoc

Add metadata to code.

@Override
public String toString() {
    return "Example";
}

13. Lambda Expressions

Simplify functional programming.

Runnable r = () -> System.out.println("Lambda Expression");
r.run();

14. Java IO

Read and write files.

import java.io.File;
File file = new File("example.txt");
System.out.println(file.exists());

15. Collection Framework

Work with dynamic data structures.

import java.util.ArrayList;
ArrayList<String> list = new ArrayList<>();
list.add("Java");
System.out.println(list.get(0));

16. Network Programming

Handle networking tasks.

import java.net.InetAddress;
InetAddress ip = InetAddress.getLocalHost();
System.out.println(ip);

17. AWT

Create GUI applications.

import java.awt.Frame;
Frame frame = new Frame("AWT Example");
frame.setSize(300, 300);
frame.setVisible(true);

18. Swing

Enhance GUIs with Swing components.

import javax.swing.JButton;
import javax.swing.JFrame;
JFrame frame = new JFrame("Swing Example");
JButton button = new JButton("Click Me");
frame.add(button);
frame.setSize(200, 200);
frame.setVisible(true);