[BAEL-9044] - Moved articles out of core-java

core-java-networking/README.md

@@ -5,3 +5,7 @@
 ### Relevant Articles
 
 - [Connecting Through Proxy Servers in Core Java](https://www.baeldung.com/java-connect-via-proxy-server)
+- [Broadcasting and Multicasting in Java](http://www.baeldung.com/java-broadcast-multicast)
+- [A Guide To UDP In Java](http://www.baeldung.com/udp-in-java)
+- [Sending Emails with Java](http://www.baeldung.com/java-email)
+- [Console I/O in Java](http://www.baeldung.com/java-console-input-output)

core-java-networking/pom.xml

@@ -13,7 +13,19 @@
         <relativePath>../parent-java</relativePath>
     </parent>
 
+    <dependencies>
+        <dependency>
+            <groupId>javax.mail</groupId>
+            <artifactId>mail</artifactId>
+            <version>${javax.mail.version}</version>
+        </dependency>
+    </dependencies>
+
     <build>
         <finalName>core-java-networking</finalName>
     </build>
+
+    <properties>
+        <javax.mail.version>1.5.0-b01</javax.mail.version>
+    </properties>	
 </project>

core-java-networking/src/main/java/com/baeldung/console/ConsoleConsoleClass.java

@@ -0,0 +1,26 @@
+package com.baeldung.console;
+
+import java.io.Console;
+
+public class ConsoleConsoleClass {
+
+    public static void main(String[] args) {
+        Console console = System.console();
+
+        if (console == null) {
+            System.out.print("No console available");
+            return;
+        }
+
+        String progLanguauge = console.readLine("Enter your favourite programming language: ");
+        console.printf(progLanguauge + " is very interesting!");
+
+        char[] pass = console.readPassword("To finish, enter password: ");
+        
+        if ("BAELDUNG".equals(pass.toString().toUpperCase()))
+            console.printf("Good! Regards!");
+        else 
+            console.printf("Nice try. Regards.");
+
+    }
+}

core-java-networking/src/main/java/com/baeldung/console/ConsoleScannerClass.java

@@ -0,0 +1,76 @@
+package com.baeldung.console;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Scanner;
+import java.util.regex.Pattern;
+
+public class ConsoleScannerClass {
+
+    public static void main(String[] args) {
+        System.out.println("Please enter your name and surname: ");
+
+        Scanner scanner = new Scanner(System.in);
+
+        String nameSurname = scanner.nextLine();
+
+        System.out.println("Please enter your gender: ");
+
+        char gender = scanner.next().charAt(0);
+
+        System.out.println("Please enter your age: ");
+
+        int age = scanner.nextInt();
+
+        System.out.println("Please enter your height in meters: ");
+
+        double height = scanner.nextDouble();
+
+        System.out.println(nameSurname + ", " + age + ", is a great " + (gender == 'm' ? "guy" : "girl") + " with " + height + " meters height" + " and " + (gender == 'm' ? "he" : "she") + " reads Baeldung.");
+
+        System.out.print("Have a good");
+        System.out.print(" one!");
+
+        System.out.println("\nPlease enter number of years of experience as a developer: ");
+
+        BufferedReader buffReader = new BufferedReader(new InputStreamReader(System.in));
+
+        int i = 0;
+
+        try {
+            i = Integer.parseInt(buffReader.readLine());
+        } catch (NumberFormatException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        } catch (IOException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+        }
+
+        System.out.println("You are a " + (i > 5 ? "great" : "good") + " developer!");
+
+        int sum = 0, count = 0;
+
+        System.out.println("Please enter your college degrees. To finish, enter baeldung website url");
+
+        while (scanner.hasNextInt()) {
+            int nmbr = scanner.nextInt();
+            sum += nmbr;
+            count++;
+        }
+        int mean = sum / count;
+
+        System.out.println("Your average degree is " + mean);
+
+        if (scanner.hasNext(Pattern.compile("www.baeldung.com")))
+            System.out.println("Correct!");
+        else
+            System.out.println("Baeldung website url is www.baeldung.com");
+
+        if (scanner != null)
+            scanner.close();
+
+    }
+
+}

core-java-networking/src/main/java/com/baeldung/mail/EmailService.java

@@ -0,0 +1,80 @@
+package com.baeldung.mail;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+import java.util.Properties;
+import javax.mail.*;
+import javax.mail.internet.InternetAddress;
+import javax.mail.internet.MimeBodyPart;
+import javax.mail.internet.MimeMessage;
+import javax.mail.internet.MimeMultipart;
+
+public class EmailService {
+
+    private String host = "";
+    private int port = 0;
+    private String username = "";
+    private String password = "";
+
+
+    public EmailService(String host, int port, String username, String password) {
+
+        this.host = host;
+        this.port = port;
+        this.username = username;
+        this.password = password;
+
+        sendMail();
+    }
+
+    private void sendMail() {
+
+        Properties prop = new Properties();
+        prop.put("mail.smtp.auth", true);
+        prop.put("mail.smtp.starttls.enable", "true");
+        prop.put("mail.smtp.host", host);
+        prop.put("mail.smtp.port", port);
+        prop.put("mail.smtp.ssl.trust", host);
+
+        Session session = Session.getInstance(prop, new Authenticator() {
+            @Override
+            protected PasswordAuthentication getPasswordAuthentication() {
+                return new PasswordAuthentication(username, password);
+            }
+        });
+
+        try {
+
+                Message message = new MimeMessage(session);
+                message.setFrom(new InternetAddress("from@gmail.com"));
+                message.setRecipients(Message.RecipientType.TO, InternetAddress.parse("to@gmail.com"));
+                message.setSubject("Mail Subject");
+
+                String msg = "This is my first email using JavaMailer";
+
+                MimeBodyPart mimeBodyPart = new MimeBodyPart();
+                mimeBodyPart.setContent(msg, "text/html");
+
+                MimeBodyPart attachmentBodyPart = new MimeBodyPart();
+                attachmentBodyPart.attachFile(new File("pom.xml"));
+
+                Multipart multipart = new MimeMultipart();
+                multipart.addBodyPart(mimeBodyPart);
+                multipart.addBodyPart(attachmentBodyPart);
+
+                message.setContent(multipart);
+
+                Transport.send(message);
+
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    public static void main(String ... args) {
+        new EmailService("smtp.mailtrap.io", 25, "87ba3d9555fae8", "91cb4379af43ed");
+    }
+
+}

core-java-networking/src/main/java/com/baeldung/networking/README.md

@@ -0,0 +1,5 @@
+### Relevant Articles:
+- [A Guide To UDP In Java](http://www.baeldung.com/udp-in-java)
+- [A Guide To HTTP Cookies In Java](http://www.baeldung.com/cookies-java)
+- [A Guide to the Java URL](http://www.baeldung.com/java-url)
+- [Working with Network Interfaces in Java](http://www.baeldung.com/java-network-interfaces)

core-java-networking/src/main/java/com/baeldung/networking/cookies/PersistentCookieStore.java

@@ -0,0 +1,57 @@
+package com.baeldung.networking.cookies;
+
+import java.net.*;
+import java.util.List;
+
+public class PersistentCookieStore implements CookieStore, Runnable {
+    CookieStore store;
+
+    public PersistentCookieStore() {
+        store = new CookieManager().getCookieStore();
+        // deserialize cookies into store
+        Runtime.getRuntime()
+            .addShutdownHook(new Thread(this));
+    }
+
+    @Override
+    public void run() {
+        // serialize cookies to persistent storage
+    }
+
+    @Override
+    public void add(URI uri, HttpCookie cookie) {
+        store.add(uri, cookie);
+
+    }
+
+    @Override
+    public List<HttpCookie> get(URI uri) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    @Override
+    public List<HttpCookie> getCookies() {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    @Override
+    public List<URI> getURIs() {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    @Override
+    public boolean remove(URI uri, HttpCookie cookie) {
+        // TODO Auto-generated method stub
+        return false;
+    }
+
+    @Override
+    public boolean removeAll() {
+        // TODO Auto-generated method stub
+        return false;
+    }
+
+}

core-java-networking/src/main/java/com/baeldung/networking/cookies/ProxyAcceptCookiePolicy.java

@@ -0,0 +1,26 @@
+package com.baeldung.networking.cookies;
+
+import java.net.*;
+
+public class ProxyAcceptCookiePolicy implements CookiePolicy {
+    String acceptedProxy;
+
+    public ProxyAcceptCookiePolicy(String acceptedProxy) {
+        this.acceptedProxy = acceptedProxy;
+    }
+
+    public boolean shouldAccept(URI uri, HttpCookie cookie) {
+        String host;
+        try {
+            host = InetAddress.getByName(uri.getHost()).getCanonicalHostName();
+        } catch (UnknownHostException e) {
+            host = uri.getHost();
+        }
+
+        if (!HttpCookie.domainMatches(acceptedProxy, host)) {
+            return false;
+        }
+
+        return CookiePolicy.ACCEPT_ORIGINAL_SERVER.shouldAccept(uri, cookie);
+    }
+}

core-java-networking/src/main/java/com/baeldung/networking/udp/EchoClient.java

@@ -0,0 +1,42 @@
+package com.baeldung.networking.udp;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+
+public class EchoClient {
+    private DatagramSocket socket;
+    private InetAddress address;
+
+    private byte[] buf;
+
+    public EchoClient() {
+        try {
+            socket = new DatagramSocket();
+            address = InetAddress.getByName("localhost");
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+    }
+
+    public String sendEcho(String msg) {
+        DatagramPacket packet = null;
+        try {
+            buf = msg.getBytes();
+            packet = new DatagramPacket(buf, buf.length, address, 4445);
+            socket.send(packet);
+            packet = new DatagramPacket(buf, buf.length);
+            socket.receive(packet);
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        String received = new String(packet.getData(), 0, packet.getLength());
+        return received;
+    }
+
+    public void close() {
+        socket.close();
+    }
+}

core-java-networking/src/main/java/com/baeldung/networking/udp/EchoServer.java

@@ -0,0 +1,42 @@
+package com.baeldung.networking.udp;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+
+public class EchoServer extends Thread {
+
+    protected DatagramSocket socket = null;
+    protected boolean running;
+    protected byte[] buf = new byte[256];
+
+    public EchoServer() throws IOException {
+        socket = new DatagramSocket(4445);
+    }
+
+    public void run() {
+        running = true;
+
+        while (running) {
+            try {
+
+                DatagramPacket packet = new DatagramPacket(buf, buf.length);
+                socket.receive(packet);
+                InetAddress address = packet.getAddress();
+                int port = packet.getPort();
+                packet = new DatagramPacket(buf, buf.length, address, port);
+                String received = new String(packet.getData(), 0, packet.getLength());
+                if (received.equals("end")) {
+                    running = false;
+                    continue;
+                }
+                socket.send(packet);
+            } catch (IOException e) {
+                e.printStackTrace();
+                running = false;
+            }
+        }
+        socket.close();
+    }
+}

core-java-networking/src/main/java/com/baeldung/networking/udp/broadcast/BroadcastingClient.java

@@ -0,0 +1,85 @@
+package com.baeldung.networking.udp.broadcast;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.net.SocketException;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class BroadcastingClient {
+    private DatagramSocket socket;
+    private InetAddress address;
+    private int expectedServerCount;
+    private byte[] buf;
+
+    public BroadcastingClient(int expectedServerCount) throws Exception {
+        this.expectedServerCount = expectedServerCount;
+        this.address = InetAddress.getByName("255.255.255.255");
+    }
+
+    public int discoverServers(String msg) throws IOException {
+        initializeSocketForBroadcasting();
+        copyMessageOnBuffer(msg);
+
+        // When we want to broadcast not just to local network, call listAllBroadcastAddresses() and execute broadcastPacket for each value.
+        broadcastPacket(address);
+
+        return receivePackets();
+    }
+
+    List<InetAddress> listAllBroadcastAddresses() throws SocketException {
+        List<InetAddress> broadcastList = new ArrayList<>();
+        Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
+        while (interfaces.hasMoreElements()) {
+            NetworkInterface networkInterface = interfaces.nextElement();
+
+            if (networkInterface.isLoopback() || !networkInterface.isUp()) {
+                continue;
+            }
+
+            broadcastList.addAll(networkInterface.getInterfaceAddresses()
+                .stream()
+                .filter(address -> address.getBroadcast() != null)
+                .map(address -> address.getBroadcast())
+                .collect(Collectors.toList()));
+        }
+        return broadcastList;
+    }
+
+    private void initializeSocketForBroadcasting() throws SocketException {
+        socket = new DatagramSocket();
+        socket.setBroadcast(true);
+    }
+
+    private void copyMessageOnBuffer(String msg) {
+        buf = msg.getBytes();
+    }
+
+    private void broadcastPacket(InetAddress address) throws IOException {
+        DatagramPacket packet = new DatagramPacket(buf, buf.length, address, 4445);
+        socket.send(packet);
+    }
+
+    private int receivePackets() throws IOException {
+        int serversDiscovered = 0;
+        while (serversDiscovered != expectedServerCount) {
+            receivePacket();
+            serversDiscovered++;
+        }
+        return serversDiscovered;
+    }
+
+    private void receivePacket() throws IOException {
+        DatagramPacket packet = new DatagramPacket(buf, buf.length);
+        socket.receive(packet);
+    }
+
+    public void close() {
+        socket.close();
+    }
+}

core-java-networking/src/main/java/com/baeldung/networking/udp/broadcast/BroadcastingEchoServer.java

@@ -0,0 +1,44 @@
+package com.baeldung.networking.udp.broadcast;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+
+public class BroadcastingEchoServer extends Thread {
+
+    protected DatagramSocket socket = null;
+    protected boolean running;
+    protected byte[] buf = new byte[256];
+
+    public BroadcastingEchoServer() throws IOException {
+        socket = new DatagramSocket(null);
+        socket.setReuseAddress(true);
+        socket.bind(new InetSocketAddress(4445));
+    }
+
+    public void run() {
+        running = true;
+
+        while (running) {
+            try {
+                DatagramPacket packet = new DatagramPacket(buf, buf.length);
+                socket.receive(packet);
+                InetAddress address = packet.getAddress();
+                int port = packet.getPort();
+                packet = new DatagramPacket(buf, buf.length, address, port);
+                String received = new String(packet.getData(), 0, packet.getLength());
+                if (received.equals("end")) {
+                    running = false;
+                    continue;
+                }
+                socket.send(packet);
+            } catch (IOException e) {
+                e.printStackTrace();
+                running = false;
+            }
+        }
+        socket.close();
+    }
+}

core-java-networking/src/main/java/com/baeldung/networking/udp/multicast/MulticastEchoServer.java

@@ -0,0 +1,41 @@
+package com.baeldung.networking.udp.multicast;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.InetAddress;
+import java.net.MulticastSocket;
+
+public class MulticastEchoServer extends Thread {
+
+    protected MulticastSocket socket = null;
+    protected byte[] buf = new byte[256];
+    protected InetAddress group = null;
+
+    public MulticastEchoServer() throws IOException {
+        socket = new MulticastSocket(4446);
+        socket.setReuseAddress(true);
+        group = InetAddress.getByName("230.0.0.0");
+        socket.joinGroup(group);
+    }
+
+    public void run() {
+        try {
+            while (true) {
+                DatagramPacket packet = new DatagramPacket(buf, buf.length);
+                socket.receive(packet);
+                InetAddress address = packet.getAddress();
+                int port = packet.getPort();
+                packet = new DatagramPacket(buf, buf.length, address, port);
+                String received = new String(packet.getData(), 0, packet.getLength());
+                if (received.equals("end")) {
+                    break;
+                }
+                socket.send(packet);
+            }
+            socket.leaveGroup(group);
+            socket.close();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}

core-java-networking/src/main/java/com/baeldung/networking/udp/multicast/MulticastingClient.java

@@ -0,0 +1,53 @@
+package com.baeldung.networking.udp.multicast;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+
+public class MulticastingClient {
+    private DatagramSocket socket;
+    private InetAddress group;
+    private int expectedServerCount;
+    private byte[] buf;
+
+    public MulticastingClient(int expectedServerCount) throws Exception {
+        this.expectedServerCount = expectedServerCount;
+        this.socket = new DatagramSocket();
+        this.group = InetAddress.getByName("230.0.0.0");
+    }
+
+    public int discoverServers(String msg) throws IOException {
+        copyMessageOnBuffer(msg);
+        multicastPacket();
+
+        return receivePackets();
+    }
+
+    private void copyMessageOnBuffer(String msg) {
+        buf = msg.getBytes();
+    }
+
+    private void multicastPacket() throws IOException {
+        DatagramPacket packet = new DatagramPacket(buf, buf.length, group, 4446);
+        socket.send(packet);
+    }
+
+    private int receivePackets() throws IOException {
+        int serversDiscovered = 0;
+        while (serversDiscovered != expectedServerCount) {
+            receivePacket();
+            serversDiscovered++;
+        }
+        return serversDiscovered;
+    }
+
+    private void receivePacket() throws IOException {
+        DatagramPacket packet = new DatagramPacket(buf, buf.length);
+        socket.receive(packet);
+    }
+
+    public void close() {
+        socket.close();
+    }
+}

core-java-networking/src/main/resources/logback.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <logger name="org.springframework" level="WARN" />
+    <logger name="org.springframework.transaction" level="WARN" />
+
+    <!-- in order to debug some marshalling issues, this needs to be TRACE -->
+    <logger name="org.springframework.web.servlet.mvc" level="WARN" />
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

core-java-networking/src/test/java/com/baeldung/networking/udp/UDPLiveTest.java

@@ -0,0 +1,38 @@
+package com.baeldung.networking.udp;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+
+public class UDPLiveTest {
+    private EchoClient client;
+
+    @Before
+    public void setup() throws IOException {
+        new EchoServer().start();
+        client = new EchoClient();
+    }
+
+    @Test
+    public void whenCanSendAndReceivePacket_thenCorrect1() {
+        String echo = client.sendEcho("hello server");
+        assertEquals("hello server", echo);
+        echo = client.sendEcho("server is working");
+        assertFalse(echo.equals("hello server"));
+    }
+
+    @After
+    public void tearDown() {
+        stopEchoServer();
+        client.close();
+    }
+
+    private void stopEchoServer() {
+        client.sendEcho("end");
+    }
+}

core-java-networking/src/test/java/com/baeldung/networking/udp/broadcast/BroadcastLiveTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.networking.udp.broadcast;
+
+import org.junit.After;
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.junit.Assert.assertEquals;
+
+public class BroadcastLiveTest {
+    private BroadcastingClient client;
+
+    @Test
+    public void whenBroadcasting_thenDiscoverExpectedServers() throws Exception {
+        int expectedServers = 4;
+        initializeForExpectedServers(expectedServers);
+
+        int serversDiscovered = client.discoverServers("hello server");
+        assertEquals(expectedServers, serversDiscovered);
+    }
+
+    private void initializeForExpectedServers(int expectedServers) throws Exception {
+        for (int i = 0; i < expectedServers; i++) {
+            new BroadcastingEchoServer().start();
+        }
+
+        client = new BroadcastingClient(expectedServers);
+    }
+
+    @After
+    public void tearDown() throws IOException {
+        stopEchoServer();
+        client.close();
+    }
+
+    private void stopEchoServer() throws IOException {
+        client.discoverServers("end");
+    }
+}

core-java-networking/src/test/java/com/baeldung/networking/udp/multicast/MulticastLiveTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.networking.udp.multicast;
+
+import org.junit.After;
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.junit.Assert.assertEquals;
+
+public class MulticastLiveTest {
+    private MulticastingClient client;
+
+    @Test
+    public void whenBroadcasting_thenDiscoverExpectedServers() throws Exception {
+        int expectedServers = 4;
+        initializeForExpectedServers(expectedServers);
+
+        int serversDiscovered = client.discoverServers("hello server");
+        assertEquals(expectedServers, serversDiscovered);
+    }
+
+    private void initializeForExpectedServers(int expectedServers) throws Exception {
+        for (int i = 0; i < expectedServers; i++) {
+            new MulticastEchoServer().start();
+        }
+
+        client = new MulticastingClient(expectedServers);
+    }
+
+    @After
+    public void tearDown() throws IOException {
+        stopEchoServer();
+        client.close();
+    }
+
+    private void stopEchoServer() throws IOException {
+        client.discoverServers("end");
+    }
+}