Lambdas simplify the code by allowing concise representations of functional interfaces.
Lambdas are written as `(parameters) -> {expression or statement}` in Java.
List numbers = Arrays.asList(1, 2, 3);
numbers.forEach(n -> System.out.println(n));
This example shows how to use a lambda for efficient iteration.
The Stream API in Java provides easy parallel processing of data collections.
With Java Streams, you can process data concurrently by simply using parallel streams.
List numbers = Arrays.asList(1, 2, 3, 4, 5);
numbers.parallelStream().forEach(System.out::println);
This example demonstrates parallel data processing using the Stream API.
Java’s module system allows developers to group related packages into modules.
With modules, you can control which parts of your code are accessible from outside.
module com.example.myapp {
requires java.base;
exports com.example.myapp.core;
}
This example shows how to define a module and export packages.
The Observer Pattern allows an object to notify other objects of state changes.
Implement Observer and Observable to create a publish-subscribe system.
import java.util.Observable;
import java.util.Observer;
class NewsAgency extends Observable {
void publishNews(String news) {
setChanged();
notifyObservers(news);
}
}
class NewsChannel implements Observer {
public void update(Observable o, Object arg) {
System.out.println("Breaking News: " + arg);
}
}
NewsAgency agency = new NewsAgency();
NewsChannel channel = new NewsChannel();
agency.addObserver(channel);
agency.publishNews("New Java Release!");
This example demonstrates the implementation of the Observer Pattern in Java.
CompletableFuture is used for asynchronous programming and managing tasks.
It supports non-blocking operations and chaining of tasks.
CompletableFuture.supplyAsync(() -> {
return "Hello";
}).thenAccept(result -> {
System.out.println(result);
});
This example shows how CompletableFuture handles asynchronous tasks.
Java’s memory model defines how variables are read and written in a multithreaded environment.
It ensures visibility of variables between threads and atomicity of operations.
class SharedResource {
private int counter = 0;
public synchronized void increment() {
counter++;
}
public int getCounter() {
return counter;
}
}
This example demonstrates synchronization to ensure proper memory visibility in multithreading.
Serialization converts objects to byte streams for storage or transmission.
Deserialization reconstructs objects from byte streams.
import java.io.*;
class Person implements Serializable {
String name;
int age;
Person(String name, int age) {
this.name = name;
this.age = age;
}
}
// Serialization
FileOutputStream fileOut = new FileOutputStream("person.ser");
ObjectOutputStream out = new ObjectOutputStream(fileOut);
out.writeObject(new Person("John Doe", 30));
out.close();
fileOut.close();
// Deserialization
FileInputStream fileIn = new FileInputStream("person.ser");
ObjectInputStream in = new ObjectInputStream(fileIn);
Person p = (Person) in.readObject();
in.close();
fileIn.close();
This example demonstrates Java’s serialization and deserialization process.
Java’s memory model defines how variables are read and written in a multithreaded environment.
It ensures visibility of variables between threads and atomicity of operations.
class SharedResource {
private int counter = 0;
public synchronized void increment() {
counter++;
}
public int getCounter() {
return counter;
}
}
This example demonstrates synchronization to ensure proper memory visibility in multithreading.
The Observer Pattern allows an object to notify other objects of state changes.
Implement Observer and Observable to create a publish-subscribe system.
import java.util.Observable;
import java.util.Observer;
class NewsAgency extends Observable {
void publishNews(String news) {
setChanged();
notifyObservers(news);
}
}
class NewsChannel implements Observer {
public void update(Observable o, Object arg) {
System.out.println("Breaking News: " + arg);
}
}
NewsAgency agency = new NewsAgency();
NewsChannel channel = new NewsChannel();
agency.addObserver(channel);
agency.publishNews("New Java Release!");
This example demonstrates the implementation of the Observer Pattern in Java.
Serialization converts objects to byte streams for storage or transmission.
Deserialization reconstructs objects from byte streams.
import java.io.*;
class Person implements Serializable {
String name;
int age;
Person(String name, int age) {
this.name = name;
this.age = age;
}
}
// Serialization
FileOutputStream fileOut = new FileOutputStream("person.ser");
ObjectOutputStream out = new ObjectOutputStream(fileOut);
out.writeObject(new Person("John Doe", 30));
out.close();
fileOut.close();
// Deserialization
FileInputStream fileIn = new FileInputStream("person.ser");
ObjectInputStream in = new ObjectInputStream(fileIn);
Person p = (Person) in.readObject();
in.close();
fileIn.close();
This example demonstrates Java’s serialization and deserialization process.