Initial commit

Problem 3.18/SocketClient.java

@@ -0,0 +1,35 @@
+import java.net.*;
+import java.io.*;
+import java.util.Scanner;
+
+public class SocketClient {
+    public static void main(String[] args) {
+        Socket sock = null;
+        Scanner scanner = null;
+        try {
+            sock = new Socket("127.0.0.1", 6017);
+            scanner = new Scanner(System.in);
+            DataOutputStream outputStream = new DataOutputStream(sock.getOutputStream());
+            DataInputStream inputStream = new DataInputStream(sock.getInputStream());
+            while (true) {
+                try {
+                    System.out.print("Input: ");
+                    String message = scanner.nextLine();
+                    outputStream.writeUTF(message);
+                    System.out.println("Echo: " + inputStream.readUTF());
+                } catch (IOException e) {
+                    System.err.println(e);
+                }
+            }
+        }
+        catch (IOException ioe) {
+            System.err.println(ioe);
+        }
+        finally {
+            try {
+                scanner.close();
+                sock.close();
+            } catch (IOException e) {}
+        }
+    }
+}

Problem 3.18/SocketServer.java

@@ -0,0 +1,37 @@
+import java.net.*;
+import java.io.*;
+
+public class SocketServer {
+    public static void main(String[] args) {
+        ServerSocket sock = null;
+        Socket client = null;
+        try {
+            sock = new ServerSocket(6017);
+            client = sock.accept();
+            DataInputStream inputStream = new DataInputStream(client.getInputStream());
+            DataOutputStream outputStream = new DataOutputStream(client.getOutputStream());
+            while (true) {
+                try {
+                    String message = inputStream.readUTF();
+                    System.out.println("Client: " + message);
+                    outputStream.writeUTF(message);
+                } catch (IOException e) {
+                    if (e.getMessage().equals("null")) {
+                        break;
+                    }
+                }
+            }
+            inputStream.close();
+            outputStream.close();
+            client.close();
+            sock.close();
+        }
+        catch (IOException ioe) {
+            try {
+                sock.close();
+                client.close();
+            } catch (IOException e) {}
+            System.err.println(ioe);
+        }
+    }
+}