Question

PROBLEM: Design and implement a Java program that enables two users to chat. Using GUIs implement one user as the server and the other as the client. The sever has two text areas: one for entering text and the other (noneditable) for displaying text received from the client. The client has two text areas: one for receiving text from the server and the other for entering text. When the user presses the enter key, the current line is sent to the server or client.

Answer 1

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//MultiClient.java

import java.io.*;
import java.net.*;
public class MultiClient
{
public static void main(String[] args) throws Exception
{
Socket sock = new Socket("127.0.0.1", 6789);
// reading from keyboard (keyRead object)
BufferedReader keyRead = new BufferedReader(new InputStreamReader(System.in));
// sending to client (pwrite object)
OutputStream ostream = sock.getOutputStream();
PrintWriter pwrite = new PrintWriter(ostream, true);

// receiving from server ( receiveRead object)
InputStream istream = sock.getInputStream();
BufferedReader receiveRead = new BufferedReader(new InputStreamReader(istream));

System.out.println("Start the Chat, type and press Enter key");

String receiveMessage, sendMessage;   
while(true)
{
sendMessage = keyRead.readLine(); // keyboard reading
pwrite.println(sendMessage); // sending to server
pwrite.flush(); // flush the data
if((receiveMessage = receiveRead.readLine()) != null) //receive from server
{
System.out.println(receiveMessage); // displaying at DOS prompt
}   
}   
}
}

//MultiServer.java

import java.io.*;
import java.net.*;
public class MultiServer
{
public static void main(String[] args) throws Exception
{
ServerSocket sersock = new ServerSocket(6789);
System.out.println("Server Ready !!");
Socket sock = sersock.accept( );
// reading from keyboard (keyRead object)
BufferedReader keyRead = new BufferedReader(new InputStreamReader(System.in));
   // sending to client (pwrite object)
OutputStream ostream = sock.getOutputStream();
PrintWriter pwrite = new PrintWriter(ostream, true);

// receiving from server ( receiveRead object)
InputStream istream = sock.getInputStream();
BufferedReader receiveRead = new BufferedReader(new InputStreamReader(istream));

String receiveMessage, sendMessage;   
while(true)
{
if((receiveMessage = receiveRead.readLine()) != null)
{
System.out.println(receiveMessage);   
}   
sendMessage = keyRead.readLine();
pwrite.println(sendMessage);   
pwrite.flush();
}   
}
}

o/p:

L . C:\WINDOWS\system32\cmd.exe-java MultiClient O. C:\WINDOWS\system32\cmd.exe - java MultiServer Microsoft Windows [Version 10.0.18363.7781 -sourcepath <path> Specify where to find input source files (c) 2019 Microsoft Corporation. All rights reserved. -bootclasspath <path> Override location of bootstrap class files -extdirs <dirs> Override location of installed extensions C:\Users\DELL>g: -endorseddirs <dirs> Override location of endorsed standards path -proc:{none, only} Control whether annotation processing and/or compilation is done. G:\>thread -processor <class1>, <class2>, <class3>...] Names of the annotation processors to run; bypasses de 'thread' is not recognized as an internal or externa -processorpath <path> Specify where to find annotation processors operable program or batch file. -parameters Generate metadata for reflection on method parameters -d <directory> Specify where to place generated class files G:\>cd thread -5 «directory> Specify where to place generated source files -h <directory> Specify where to place generated native header files G:\thread>javac Multiclient.java -implicit:{none, class} Specify whether or not to generate class files for implicitly reference -encoding <encoding> Specify character encoding used by source files G:\thread>java Multiclient -source <release> Provide source compatibility with specified release Start the Chat, type and press Enter key -target <release> Generate class files for specific VM version hello server how are u boi -profile <profile> Check that API used is available in the specified profile i am fine client what u want now, -version Version information -help Print a synopsis of standard options -Akey[=value] Options to pass to annotation processors -X Print a synopsis of nonstandard options -]<flag> Pass <flag> directly to the runtime system -Werror Terminate compilation if warnings occur @<filename> Read options and filenames from file G:\>cd thread G:\thread>javac MultiServer.java G:\thread>java Multiserver Server Ready !! hello server how are u boi i am fine client what u want now A 10:19 AM D 1 26-Apr-20

C. C:\WINDOWS\system32\cmd.exe-java Server G. C:\WINDOWS\system32\cmd.exe - O X C:\Users\DELL>g: Microsoft Windows [Version 10.0.18363.778] (c) 2019 Microsoft Corporation. All rights reserved. G:\thread>javac Server.java Server.java:9: error: class SimpleFileServer is public, should be declared C:\Users\DELL>g: public class SimpleFileServer { G:\>G: \thread 1 error "G:\thread' is not recognized as an internal or external command, operable program or batch file. G:\thread>javac Server.java G:\>cdG:\thread G:\thread>java Server The filename, directory name, or volume label syntax is incorrect. Waiting... Accepted connection : Socket[addr=/127.0.0.1,port=56412, localport=132671 G:\>cd thread! Exception in thread "main" java.io.FileNotFoundException: G:\thread\hello.t at java.io.FileInputStream.open(Native Method) G:\thread>javac Client.java at java.io.FileInputStream.open(FileInputStream.java:195) at java.io.FileInputStream.<init>(FileInputStream.java:138) G:\thread>java Client at Server.main(Server.java:30) Connecting... Exception in thread "main" java.lang. ArrayIndexOutOfBounds Exception G:\thread>javac Server.java at java.lang.System.arraycopy (Native Method) Server.java:12: error: illegal escape character at java.io.BufferedoutputStream.write(BufferedOutputStream.java:1 public final static String FILE_TO_SEND ="G:\thread\hello.txt"; // you m28) at Client.main(Client.java:43) 1 error G:\thread>javac Client.java G:\thread>javac Server.java G:\thread>java Client G:\thread>java Server Connecting... Waiting... File G:/thread/hello.txt downloaded (104 bytes read) Accepted connection : Socket[addr=/127.0.0.1, port=56437, localport=13267] Sending G:/thread/hello.txt(104 bytes) G: \thread> Done. Waiting... 10:34 AM ^ M D 1 26-Apr-20