Welcome to Advanced Java Tutorials
Welcome to the advanced tutorials section of Java World. Here, you’ll find resources to help you master advanced Java programming concepts. Our tutorials cover a wide range of topics that will enhance your coding capabilities and prepare you for complex Java projects.
Section 1: Advanced Object-Oriented Programming
Generics
Generics in Java allow you to define classes, interfaces, and methods with type parameters. This tutorial will teach you how to use generics.
class GenericClass {
private T value;
public void setValue(T value) {
this.value = value;
}
public T getValue() {
return value;
}
}
public class Main {
public static void main(String[] args) {
GenericClass stringInstance = new GenericClass<>();
stringInstance.setValue("Hello");
System.out.println(stringInstance.getValue());
GenericClass integerInstance = new GenericClass<>();
integerInstance.setValue(123);
System.out.println(integerInstance.getValue());
}
}
Annotations
Annotations in Java provide metadata about the program. This tutorial will teach you how to use annotations.
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
@Retention(RetentionPolicy.RUNTIME)
@interface MyAnnotation {
String value();
}
public class Main {
@MyAnnotation(value = "Hello, World!")
public void myMethod() {
System.out.println("This is my method.");
}
public static void main(String[] args) throws Exception {
Main main = new Main();
Method method = main.getClass().getMethod("myMethod");
MyAnnotation annotation = method.getAnnotation(MyAnnotation.class);
System.out.println("Annotation value: " + annotation.value());
}
}
Reflection
Reflection in Java is a powerful mechanism that allows the inspection and manipulation of classes, interfaces, fields, and methods at runtime.
import java.lang.reflect.Method;
public class Main {
public static void main(String[] args) throws Exception {
Class<?> cls = Class.forName("java.lang.String");
Method method = cls.getMethod("substring", int.class);
String result = (String) method.invoke("Hello, World!", 7);
System.out.println(result); // Outputs: World!
}
}
Section 2: Advanced Data Structures and Algorithms
Advanced Collections
Java Collections Framework provides advanced collections like ConcurrentHashMap
and CopyOnWriteArrayList
for use in concurrent environments.
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
public class Main {
public static void main(String[] args) {
ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<>();
map.put("One", 1);
map.put("Two", 2);
System.out.println(map);
CopyOnWriteArrayList list = new CopyOnWriteArrayList<>();
list.add("One");
list.add("Two");
System.out.println(list);
}
}
Streams API
The Streams API in Java provides a functional approach to processing sequences of elements. This tutorial will teach you how to use the Streams API.
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
public class Main {
public static void main(String[] args) {
List names = Arrays.asList("Alice", "Bob", "Charlie");
List upperCaseNames = names.stream()
.map(String::toUpperCase)
.collect(Collectors.toList());
upperCaseNames.forEach(System.out::println);
}
}
Lambda Expressions
Lambda expressions in Java provide a clear and concise way to represent one method interface using an expression.
@FunctionalInterface
interface MyFunctionalInterface {
void display();
}
public class Main {
public static void main(String[] args) {
MyFunctionalInterface msg = () -> {
System.out.println("Hello, this is a lambda expression.");
};
msg.display();
}
}
Section 3: Advanced Concurrency
Thread Pools
Thread pools are used to manage a pool of worker threads. This tutorial will teach you how to use thread pools in Java.
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class Main {
public static void main(String[] args) {
ExecutorService executor = Executors.newFixedThreadPool(5);
for (int i = 0; i < 10; i++) {
Runnable worker = new WorkerThread("" + i);
executor.execute(worker);
}
executor.shutdown();
while (!executor.isTerminated()) {
}
System.out.println("Finished all threads");
}
}
class WorkerThread implements Runnable {
private String message;
public WorkerThread(String message) {
this.message = message;
}
public void run() {
System.out.println(Thread.currentThread().getName() + " (Start) message = " + message);
processMessage();
System.out.println(Thread.currentThread().getName() + " (End)");
}
private void processMessage() {
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
Concurrency Utilities
Java provides several utilities for concurrent programming, such as CountDownLatch
and CyclicBarrier
.
import java.util.concurrent.CountDownLatch;
public class Main {
public static void main(String[] args) throws InterruptedException {
CountDownLatch latch = new CountDownLatch(3);
Runnable task = () -> {
System.out.println(Thread.currentThread().getName() + " is running");
latch.countDown();
};
new Thread(task).start();
new Thread(task).start();
new Thread(task).start();
latch.await();
System.out.println("All threads have finished");
}
}
Advanced Synchronization
Advanced synchronization techniques include using explicit locks, such as ReentrantLock
, and concurrent collections for thread-safe operations.
import java.util.concurrent.locks.ReentrantLock;
public class Main {
public static void main(String[] args) {
ReentrantLock lock = new ReentrantLock();
Runnable task = () -> {
lock.lock();
try {
System.out.println(Thread.currentThread().getName() + " has acquired the lock");
} finally {
lock.unlock();
}
};
new Thread(task).start();
new Thread(task).start();
}
}
Continue exploring our advanced tutorials to master Java programming.