Problem in TCP program (Java)

Question

Can someone help me debug this program?

Below is the server code:

package networking; import java.io.IOException; import java.io.PrintWriter; import java.net.ServerSocket; import java.net.Socket; import java.util.Scanner; class TcpServer { public static void main(String[] args) throws IOException { ServerSocket serverSocket = new ServerSocket(5555); while (true) { Socket client = serverSocket.accept(); Scanner reader = new Scanner(client.getInputStream()); PrintWriter writer = new PrintWriter(client.getOutputStream()); String inputString = reader.nextLine(); System.out.println("Received from client : " + inputString); writer.write(inputString.toUpperCase()); client.close(); } } } 

And this is the client code:

 package networking; import java.io.PrintWriter; import java.io.IOException; import java.net.Socket; import java.util.Scanner; class TcpClient { public static void main(String[] args) throws IOException { Socket client = new Socket("localhost", 5555); PrintWriter writer = new PrintWriter(client.getOutputStream()); Scanner reader=new Scanner(client.getInputStream()); writer.println("oPen SOurCe RUleS !"); System.out.println("Received from server : "+reader.nextLine()); client.close(); } } 

The problem is that when this program starts, the client and server go into an undefined waiting state. Can someone tell me what is wrong with this code?

Thanks in advance!

Answer 1

Have you tried Flushing PrintWriter ?

You close the stream, but you never tell the author that you are going to do this.