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After successfully establishing a socket connection, how does the server actively send string messages to the client?

I am building a server. I hope that after the Java server and the C# client are connected, I can send information from the HTML to the Java server, and then the Java server sends this information to the client.But I can't get the socket after the successful establishment in the service layer, so my Java server can only send fixed information to the client.
I tried using Class object = new Class(); object.setObject(socket); to save the socket, but when I call this object in the service layer, I get null;
I tried to save the socket using (Map) socket.put("socket", socket), but when I call this method in the service layer, I get null.
This is the code to make the socket. from SocketThread.java
public void run() {
ServerSocket serverSocket = null;
try{
serverSocket = new ServerSocket(5656);
LOGGER.info("socket server start, monitor 5656 port ! ");
Socket socket = serverSocket.accept();
new SocketClientRequest(socket).start();
LOGGER.info("send success ! ");
}catch (Exception ex){
LOGGER.error("send fail ! ");
}
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
LOGGER.error("服务器延时重启失败 ! ");
}
}
This is a method of reading the information sent by the client using the socket and sending the information to the client. from SocketClientRequest.java
public void run() {
try {
//获取socket中的数据
bufferedInputStream = new
BufferedInputStream(socket.getInputStream());
byte[] clientCharStream = new byte[messageLengthBytes];
bufferedInputStream.read(clientCharStream);
System.out.println(new String(clientCharStream, "utf-8"));
OutputStream out = socket.getOutputStream();
out.write(new String("welcome_send_server!").getBytes());
} catch (IOException e) {
LOGGER.error("read massage error [{}]", e);
}
}
Create a connection when the project starts
#EnableScheduling
#SpringBootApplication
public class GzserverApplication {
public static void main(String[] args) {
SpringApplication.run(GzserverApplication.class, args);
SocketServer socketServer = new SocketServer();
socketServer.start();
}
}
Until this step, everything is fine, but the key problem is coming.
I need to send information to the client through my controller.
this is controller
#ResponseBody
#RequestMapping(value = "firstSend)
public SResult<String> firstSend(String uName, String pNum, String time){
try{
return httpService.firstSend(uName, pNum, time);
}catch (Exception ex){
LOGGER.error(ex.getMessage(), ex);
}
return SResult.failure("fail of connect");
}
this is service
public SResult<String> firstSend(String uName, String pNum, String time) throws Exception {
String token = TokenUtil.sign(uName);
System.out.println("token code : "+token);
SocketObject socketObject = new SocketObject();
Map<String, Socket> socketMap = socketObject.socket();
Socket socket1 = socketMap.get("Socket"); // is null
Socket socket2 = socketObject.getSocket(); // is null
return SResult.success(token);
}
I hope that after the connection is successfully created, the socket can be used in the service layer, and the information is sent to the client through the socket, but no matter what I do, the socket is null in the service layer.please give me a help, thank you very much

You should not be dealing with Sockets if using Spring. Spring is a very extensive abstraction layer, that lets you avoid having to deal with the nasty details that Sockets introduce.
In your controller, you call: SocketObject socketObject = new SocketObject(); This creates a new object, presumably with a null-initialized Socket object. Nowhere in this code do you pass a socket object from the main() scope to any other scope (for example using a method named setSocket(Socket socket).
However, and I cannot stress this enough, you should not use Sockets in Spring. Think about what problem you are trying to solve, and ask yourself (why do I need to send information to the client). It is likely that Spring has a module that will do this for you in a much more scalable and manageable way.
For example, perhaps you need to establish 2-way communication between the server and the client, and need to post information to the client periodically. In this case, the WebSocket protocol (and associated Spring Websocket library) might be for you.
This is likely an XY problem. If you edit your question to illustrate the functionality you are trying to implement, it may be easier to help

Connection refused error when using sockets between C# (server) and Java (Client) applications

I am trying to create a socket connection between a .Net server application and Java Client Application.
I am getting an error from the java client application:
Connection refused: connect
Notes:
Communicating with a .Net Client Application, works fine.
I have disables the windows firewall
Undoubtedly, I am running the server application in the background and then I am running the client application
Following are my server code (C#):
public class Server
{
public Server()
{
CreateListener();
}
public void CreateListener()
{
// Create an instance of the TcpListener class.
TcpListener tcpListener = null;
IPAddress ipAddress = Dns.GetHostEntry("localhost").AddressList[0];
string output;
try
{
// Set the listener on the local IP address
// and specify the port.
tcpListener = new TcpListener(ipAddress, 13);
tcpListener.Start();
output = "Waiting for a connection...";
}
catch (Exception e)
{
output = "Error: " + e.ToString();
MessageBox.Show(output);
}
}
}
and client application code (Java):
public class smtpClient {
public void Send() {
Socket smtpSocket = null;
DataOutputStream os = null;
DataInputStream is = null;
try {
smtpSocket = new Socket("localhost", 13); // FAILURE
os = new DataOutputStream(smtpSocket.getOutputStream());
is = new DataInputStream(smtpSocket.getInputStream());
} catch (UnknownHostException e) {
System.err.println("Don't know about host: hostname");
} catch (IOException e) {
System.err.println(e.getMessage());
}
}
It fails at the following line in the Java Client Application:
smtpSocket = new Socket("localhost", 13);

I can't tell what is the issue you are facing, but you need to start with a solid foundation to discover these issues.
As a rule of thumb, you should always write one piece (typically the server) first and verify connectivity (say using telnet) and then write the other piece (typically client) and verify its connectivity.
I always keep a Standard Client and Server handy to test whether its my code or its the environment/configuration.
Below is a sample code that works fine to test connectivity.
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
class ClientServer {
static void Main() {
new Thread(() => { StartServer("localhost", 5013); }).Start();
Thread.Sleep(100);
Console.WriteLine("\nPress enter to start the client...");
Console.ReadLine();
StartClient("localhost", 5013);
}
public static void StartServer(string serverInterface, int port) {
try {
IPHostEntry hostInfo = Dns.GetHostEntry(serverInterface);
string hostName = hostInfo.HostName;
IPAddress ipAddress = hostInfo.AddressList[0];
var server = new TcpListener(ipAddress, port);
server.Start();
Console.WriteLine($"Waiting for a connection at {server.LocalEndpoint}");
Console.WriteLine("Press ctrl+c to exit server...");
while (true) {
TcpClient client = server.AcceptTcpClient();
Console.WriteLine($"Server says - Client connected: {client.Client.RemoteEndPoint}");
ThreadPool.QueueUserWorkItem((state) => {
using (var _client = (TcpClient)state)
using (NetworkStream stream = _client.GetStream()) {
string msg = stream.ReadAsciiData();
if (msg == "Hello!") {
stream.WriteAsciiData($"Time:{DateTime.Now: yyyy/MM/dd HH:mm zzz}. Server name is {hostName}");
}
}
}, client);
}
} catch (Exception e) {
Console.WriteLine(e);
}
}
public static void StartClient(string serverInterface, int port) {
Console.WriteLine("Client started...");
try {
using (var client = new TcpClient(serverInterface, port))
using (NetworkStream stream = client.GetStream()) {
Console.WriteLine("Client says - Hello!");
stream.Write(Encoding.ASCII.GetBytes("Hello!"));
string msg = stream.ReadAsciiData();
Console.WriteLine($"Client says - Message from server: Server#{client.Client.RemoteEndPoint}: {msg}");
}
} catch (Exception e) {
Console.WriteLine(e);
}
Console.WriteLine("Client exited");
}
}
static class Utils {
public static void WriteAsciiData(this NetworkStream stream, string data) {
stream.Write(Encoding.ASCII.GetBytes(data));
}
public static string ReadAsciiData(this NetworkStream stream) {
var buffer = new byte[1024];
int read = stream.Read(buffer, 0, buffer.Length);
return Encoding.ASCII.GetString(buffer, 0, read);
}
public static void Write(this NetworkStream stream, byte[] data) {
stream.Write(data, 0, data.Length);
}
}
Now to your specific problem,
The choice of port 13, is not ideal for testing. Usually all ports below 1024 are considered privileged. i.e. a firewall or antivirus might block your attempt to listen on that port
Remember that IPV6 addresses plays a role. Your machine might have that enabled or disabled based on your configuration. You want to make sure that if your server is listening on a IPv6 interface, then your client also connects on the same
Which brings us to another related point: Irrespective of you are using IPv6 interface or not, the client needs to connect to the same interface the server is listening on. This might seem obvious, but is often missed. A typical machine
has at-least 2 interfaces: One for localhost (127...* called loopback interface) and another non local (typically 10...* or 192...*, but not restricted to it). It can so happen (especially when you pick the first available interface to bind your server without knowing which one it is) that server might be listening on non loopback interface like say 192.168.1.10 interface and the client might be connecting to 127.0.0.1, and you can see why the client will get "connection refused" errors
The sample code above works and you can test your code with it. You can us telnet for a client or just my sample code. You can play around changing the serverInterface values to some surprising discoveries which are accentuated by
ipAddress = hostInfo.AddressList[0] line
Hope this helps you with your debugging

Creating a HTTPS Server in Java - Where is the local Certificates?

i found some tutorial to handle with https server and a https client. i created some keystore and it works fine. But i have some question which is not clear from the tutorial.
this is my https-server
public class HTTPSServer {
private int port = 9999;
private boolean isServerDone = false;
public static void main(String[] args) {
HTTPSServer server = new HTTPSServer();
server.run();
}
HTTPSServer() {
}
HTTPSServer(int port) {
this.port = port;
}
// Create the and initialize the SSLContext
private SSLContext createSSLContext() {
try {
//Returns keystore object in definied type, here jks
KeyStore keyStore = KeyStore.getInstance("JKS");
//loads the keystore from givin input stream, and the password to unclock jks
keyStore.load(new FileInputStream("x509-ca.jks"), "password".toCharArray());
// Create key manager
KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance("SunX509");
keyManagerFactory.init(keyStore, "password".toCharArray());
KeyManager[] km = keyManagerFactory.getKeyManagers();
// Create trust manager
TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance("SunX509");
trustManagerFactory.init(keyStore);
TrustManager[] tm = trustManagerFactory.getTrustManagers();
// opens a secure socket with definied protocol
SSLContext sslContext = SSLContext.getInstance("TLSv1.2");
//System.out.println(keyStore.getCertificate("root").getPublicKey());
//System.out.println(keyStore.isKeyEntry("root"));
sslContext.init(km, tm, null);
return sslContext;
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
// Start to run the server
public void run() {
SSLContext sslContext = this.createSSLContext();
try {
// Create server socket factory
SSLServerSocketFactory sslServerSocketFactory = sslContext.getServerSocketFactory();
// Create server socket
SSLServerSocket sslServerSocket = (SSLServerSocket) sslServerSocketFactory.createServerSocket(this.port);
System.out.println("SSL server started");
while (!isServerDone) {
SSLSocket sslSocket = (SSLSocket) sslServerSocket.accept();
// Start the server thread
new ServerThread(sslSocket).start();
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
// Thread handling the socket from client
static class ServerThread extends Thread {
private SSLSocket sslSocket = null;
ServerThread(SSLSocket sslSocket) {
this.sslSocket = sslSocket;
}
public void run() {
sslSocket.setEnabledCipherSuites(sslSocket.getSupportedCipherSuites());
//System.out.println("HIER: " + sslSocket.getHandshakeSession());
//Klappt nicht, auch nicht, wenn der Client diese Zeile ebenfalls besitzt
//sslSocket.setEnabledCipherSuites(new String[]{"TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256"});
try {
// Start handshake
sslSocket.startHandshake();
// Get session after the connection is established
SSLSession sslSession = sslSocket.getSession();
System.out.println(sslSession.getPeerHost());
System.out.println(sslSession.getLocalCertificates());
System.out.println("\tProtocol : " + sslSession.getProtocol());
System.out.println("\tCipher suite : " + sslSession.getCipherSuite());
System.out.println("\tSession context : " + sslSession.getSessionContext());
//System.out.println("\tPeer pricipal of peer : " + sslSession.getPeerPrincipal());
// Start handling application content
InputStream inputStream = sslSocket.getInputStream();
OutputStream outputStream = sslSocket.getOutputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
PrintWriter printWriter = new PrintWriter(new OutputStreamWriter(outputStream));
String line = null;
String[] suites = sslSocket.getSupportedCipherSuites();
for (int i = 0; i < suites.length; i++) {
//System.out.println(suites[i]);
//System.out.println(sslSession.getCipherSuite());
}
while ((line = bufferedReader.readLine()) != null) {
System.out.println("Inut : " + line);
if (line.trim().isEmpty()) {
break;
}
}
// Write data
printWriter.print("HTTP/1.1 200\r\n");
printWriter.flush();
sslSocket.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
}
And this is my output:
SSL server started
127.0.0.1
null
Protocol : TLSv1.2
Cipher suite : TLS_DH_anon_WITH_AES_128_GCM_SHA256
Session context : sun.security.ssl.SSLSessionContextImpl#781df1a4
I want to know, why the line
System.out.println(sslSession.getLocalCertificates());
prints out "null"?
Thank you a lot, Mira

From the documentation:
Certificate[] getLocalCertificates()
Returns the certificate(s) that were sent to the peer during handshaking.
Note: This method is useful only when using certificate-based cipher suites.
When multiple certificates are available for use in a handshake, the implementation chooses what it considers the "best" certificate chain available, and transmits that to the other side. This method allows the caller to know which certificate chain was actually used.
Returns:
an ordered array of certificates, with the local certificate first followed by any certificate authorities. If no certificates were sent, then null is returned.
The part we care about is "Returns the certificate(s) that were sent to the peer during handshaking.", and "This method is useful only when using certificate-based cipher suites.".
Given that it is returning null, we can assume you are not sending any certificates to the client. But it's also HTTPS, so what gives? Well, it looks like you're using TLS_DH_anon_WITH_AES_128_GCM_SHA256, which is, as the name suggests, anonymous. As per the OpenSSL Wiki:
Anonymous Diffie-Hellman uses Diffie-Hellman, but without authentication. Because the keys used in the exchange are not authenticated, the protocol is susceptible to Man-in-the-Middle attacks. Note: if you use this scheme, a call to SSL_get_peer_certificate will return NULL because you have selected an anonymous protocol. This is the only time SSL_get_peer_certificate is allowed to return NULL under normal circumstances.
While this is applicable to OpenSSL, it would appear to be the same in Java - that is, you're not using a certificate-based cipher. Someone with more knowledge of TLS would need to jump in, but it looks like AES keys are generated, and they're sent to the client, but the client has no assurance those keys came from you, whereas normally you would generate the keys, and then sign / encrypt (not 100% sure) those keys with an RSA key to prove they came from you.
To fix this, I believe you would need to select a different cipher suite, e.g. TLS_RSA_WITH_AES_128_GCM_SHA256. I'm not 100% sure how you would do this, but that would appear to be the solution.

sslSocket.setEnabledCipherSuites(sslSocket.getSupportedCipherSuites());
You are enabling all the anonymous and low-grade cipher suites, so you are allowing the server not to send a certificate, so it doesn't send one, so it doesn't give you one in getLocalCertificates().
Remove this line.

"The Transport Protocol thread failed" – "The socket is EOF" with J2SSH connection using Java

I am trying to establish an SSH connection through my Java code, but getting below exception .. I tested my connection through Putty/Winscp tools and it works fine. The problem is with my Java code...
SEVERE: The Transport Protocol thread failed
java.io.IOException: The socket is EOF
at com.sshtools.j2ssh.transport.TransportProtocolInputStream.readBufferedData(Unknown Source)
at com.sshtools.j2ssh.transport.TransportProtocolInputStream.readMessage(Unknown Source)
at com.sshtools.j2ssh.transport.TransportProtocolCommon.readMessage(Unknown Source)
at com.sshtools.j2ssh.transport.kex.DhGroup1Sha1.performClientExchange(Unknown Source)
at com.sshtools.j2ssh.transport.TransportProtocolClient.performKeyExchange(Unknown Source)
at com.sshtools.j2ssh.transport.TransportProtocolCommon.beginKeyExchange(Unknown Source)
at com.sshtools.j2ssh.transport.TransportProtocolCommon.onMsgKexInit(Unknown Source)
at com.sshtools.j2ssh.transport.TransportProtocolCommon.startBinaryPacketProtocol(Unknown Source)
at com.sshtools.j2ssh.transport.TransportProtocolCommon.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Below is my piece of Java code to establish the connection
public class MySSHClient {
static SshClient ssh = null;
static SshConnectionProperties properties = null;
SessionChannelClient session = null;
private static void MySSHClient(String hostName, String userName, String passwd )
{
try
{
// Make a client connection
ssh = new SshClient();
properties = new SshConnectionProperties();
properties.setHost("192.168.1.175");
// Connect to the host
ssh.connect(properties, new IgnoreHostKeyVerification());
// Create a password authentication instance
PasswordAuthenticationClient pwd = new PasswordAuthenticationClient();
pwd.setUsername("root");
pwd.setPassword("123456");
// Try the authentication
int result = ssh.authenticate(pwd);
// Evaluate the result
if (result==AuthenticationProtocolState.COMPLETE) {
System.out.println("Connection Authenticated");
}
}
catch(Exception e)
{
System.out.println("Exception : " + e.getMessage());
}
}//end of method.
public String execCmd(String cmd)
{
String theOutput = "";
try
{
// The connection is authenticated we can now do some real work!
session = ssh.openSessionChannel();
if ( session.executeCommand(cmd) )
{
IOStreamConnector output = new IOStreamConnector();
java.io.ByteArrayOutputStream bos = new
java.io.ByteArrayOutputStream();
output.connect(session.getInputStream(), bos );
session.getState().waitForState(ChannelState.CHANNEL_CLOSED);
theOutput = bos.toString();
}
//else
//throw Exception("Failed to execute command : " + cmd);
//System.out.println("Failed to execute command : " + cmd);
}
catch(Exception e)
{
System.out.println("Exception : " + e.getMessage());
}
return theOutput;
}
public static void main(String[] args){
MySSHClient(null, null, null);
}

Motivation
I stumbled across this question and answers while investigating the error in question java.io.IOException: The socket is EOF. Because changing the code to use some other SSH Java library is not immediately possible in my case and the stated explanation by #a3.14_Infinity was not detailed enough for me, I'd like to add my take on it.
java.io.IOException: The socket is EOF - Why?
Because this exception is not very helpful, I first tried Wireshark to see what's going on over the wire, but to no avail. So I configured the sshd_config (OpenSSH 6.9) to log on DEBUG3 level and got the answer in the /var/log/auth.log file of my test machine. It stated a fatal error while trying to negotiate the key exchange algorithm with the SSH client (the Java SSH library).
Because the SSH server and client could not agree on a mutual key exchange algorithm the OpenSSH server terminates the connection to the client. In consequence, the Java SSH library code throws the exception.
But why does it happen?
The sshtools.j2ssh (sshtools : j2ssh-core : 0.2.9) library code is pretty old and discontinued. Starting with OpenSSH 6.7 (released October, 2014) default ciphers and MAC have been altered to remove unsafe algorithms which includes the blowfish-cbc cipher. And with OpenSSH 6.9 (released June, 2015) the support for the 1024-bit diffie-hellman-group1-sha1 key exchange is disabled by default.
When you still use the prehistoric SSH Tools j2ssh library (God forbid) connecting to a newer OpenSSH server you will get the described error. The library code only offers the diffie-hellman-group1-sha1 key exchange algorithm to the OpenSSH server which it does not support by default. Thus, a secure connection cannot be established.
Cannot change the code?
If moving to another Java SSH library is not immediately possible (my case) then you can re-enable the disabled diffie-hellman-group1-sha1 key exchange algorithm in the OpenSSH's server config file sshd_config. For example like this.
Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm#openssh.com,aes256-gcm#openssh.com,chacha20-poly1305#openssh.com,blowfish-cbc
KexAlgorithms diffie-hellman-group1-sha1,diffie-hellman-group-exchange-sha1,curve25519-sha256#libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1
But let me be clear on this. The diffie-hellman-group1-sha1 key exchange algorithm as well as the blowfish-cbc cipher are turned off by default because they are insecure. Reenabling them should only be a temporary measure until you can replace this obsolete Java SSH library.
Finally, I like to point out that the suggested Java Secure Channel (JSch) library in other answers is discontinued. So, you might want to consider sshj or even ssh2j-maverick instead.
Edit: I was wrong, the Java Secure Channel JSch library is alive (JSCH 0.1.54 was released on 2016-09-03 on MavenCentral) and certainly worth your consideration. Alternatively, you may want to consider also sshj or ssh2j-maverick.
Addendum: Migration
To keep the migration effort for the sshtools.j2ssh (sshtools : j2ssh-core : 0.2.9) library minimal I looked at the commercial legacy SSH client library from SSHTOOLS (version 1.7.1). This allowed to keep the existing library integration code with few minor changes regarding library API and exception handling. Thus, if you do not want to restart from scratch then biting the bullet and sticking with SSHTOOLS is probably your best option. Finally, to gauge the migration effort I first replaced the library with SSHTOOLS' open source library ssh2j-maverick which almost has the same API as its latest commercial version (version 1.7.1).

This error ("The Transport Protocol thread failed. java.io.IOException: The socket is EOF”) occurs when j2ssh.jar file is not compatible with current SSH version of SFTP server.
You can try using Java Secure Channel (JSch) from here.
Courtesy: http://techydiary.com/the-transport-protocol-thread-failed-java-io-ioexception-the-socket-is-eof/

The following sample Code may help you,
import java.io.InputStream;
import org.apache.commons.io.IOUtils;
import com.jcraft.jsch.Channel;
import com.jcraft.jsch.ChannelExec;
import com.jcraft.jsch.JSch;
import com.jcraft.jsch.Session;
public class SSHClient {
/**
* Constant EXCUTE_CHANNEL
*/
public static final String EXCUTE_CHANNEL = "exec";
/**
* Constant STRICT_KEY_CHECKING
*/
public static final String STRICT_KEY_CHECKING = "StrictHostKeyChecking";
/** Name/ip of the remote machine/device **/
private String host;
private String userName;
private String password;
/**
* This method used to initilze user and host
*
* #param userName
* #param password
* #param host
*/
public SSHClient(String userName,String password, String host) {
super();
this.userName = userName;
this.password = password;
this.host = host;
}
/**
* This method used to execute commands remotly by using SSHV2
*
* #param host
* #param username
* #param password
* #param command
* #return
*/
public String executeCommand(String command) {
StringBuilder log = new StringBuilder();
String response = null;
Channel channel = null;
Session session = null;
try {
JSch jsch = new JSch();
JSch.setConfig(STRICT_KEY_CHECKING, Constants.NO);
session = jsch.getSession(userName, host, 22);
// If two machines have SSH passwordless logins setup, the following
// line is not needed:
session.setPassword(password);
session.connect();
channel = session.openChannel(EXCUTE_CHANNEL);
((ChannelExec) channel).setCommand(command);
// channel.setInputStream(System.in);
channel.setInputStream(null);
((ChannelExec) channel).setErrStream(System.err);
InputStream in = channel.getInputStream();
channel.connect();
response = IOUtils.toString(in);
} catch (Exception ex) {
//handle exception
} finally {
try {
if (session != null) {
session.disconnect();
}
} catch (Exception ex) {
//handle exception
}
try {
if (channel != null) {
channel.disconnect();
}
} catch (Exception ex) {
//handle exception
}
}
System.ou.println( "Response received :"+ response));
return response;
}
}

Here is the working code reused from some google source -
import ch.ethz.ssh2.Connection;
import ch.ethz.ssh2.StreamGobbler;
Connection conn = new Connection(server);
conn.connect();
boolean isAuthenticated = conn.authenticateWithPassword(user_id, password);
System.out.println("Is server - " + server + " Authenticated? " + isAuthenticated);
if (isAuthenticated == false)
throw new IOException("Authentication failed.");
ch.ethz.ssh2.Session sess = conn.openSession();
String new_commands = "";
for (int i = 0; i < commands.size(); i++) {
new_commands = new_commands + commands.get(i) + "\n";
}
System.out.println("The command executed is: " + new_commands);
sess.requestDumbPTY();
sess.execCommand(new_commands);
InputStream stdout = new StreamGobbler(sess.getStdout());
BufferedReader br = new BufferedReader(new InputStreamReader(stdout));
InputStream errStrm = new StreamGobbler(sess.getStderr());
BufferedReader stderrRdr = new BufferedReader(new InputStreamReader(errStrm));
sess.getStdin().write("EXIT\n".getBytes());
System.out.println("the output of the command is");
while (true) {
String line_out = br.readLine();
if (line_out == null) {
break;
} else {
System.out.println(line_out);
output_logs.add(line_out);
}
}
while (true) {
String line_error = stderrRdr.readLine();
if (line_error == null) {
break;
} else {
System.out.println(line_error);
output_logs.add(line_error);
}
}
output_logs.add("Exit Code:" + sess.getExitStatus());
System.out.println("ExitCode: " + sess.getExitSignal());
sess.close();
conn.close();

found a simple solution on the OS:
comment out the Cipher line in /etc/ssh/sshd_config
and run service sshd restart

MySQL jdbc + SSL

I set system properties for a SSL-enabled MySQL client, which worked fine:
System.setProperty("javax.net.ssl.trustStore","truststore");
System.setProperty("javax.net.ssl.trustStorePassword","12345");
String url = "jdbc:mysql://abc.com:3306/test?" +
"user=abc&password=123" +
"&useUnicode=true" +
"&characterEncoding=utf8&useSSL=true"
A couple days ago I found the client couldn't connect to another web site in which a commercially signed SSL certificate is installed. Obviously the overriding keystores didn't work with regular https connections.
Then I decided to build my version of SocketFactory based on StandardSocketFactory.java in MySQL Connector/J source.
I added a method to create Socket objects in public Socket connect(String hostname, int portNumber, Properties props) method.
private Socket createSSLSocket(InetAddress address, int port) {
Socket socket;
try {
InputStream trustStream = new FileInputStream(new File("truststore"));
KeyStore trustStore = KeyStore.getInstance("JKS");
// load the stream to your store
trustStore.load(trustStream, trustPassword);
// initialize a trust manager factory with the trusted store
TrustManagerFactory trustFactory = TrustManagerFactory.getInstance("PKIX", "SunJSSE"); trustFactory.init(trustStore);
// get the trust managers from the factory
TrustManager[] trustManagers = trustFactory.getTrustManagers();
// initialize an ssl context to use these managers and set as default
SSLContext sslContext = SSLContext.getInstance("SSL");
sslContext.init(null, trustManagers, null);
if(address == null) {
socket = sslContext.getSocketFactory().createSocket();
} else {
socket = sslContext.getSocketFactory().createSocket(address, port);
}
} catch (Exception e) {
System.out.println(e.getLocalizedMessage());
return null;
}
return socket;
}
The url passed to jdbc driver is changed to:
String url = "jdbc:mysql://abc.com:3306/test?" +
"user=abc&password=123" +
"&useUnicode=true" +
"&characterEncoding=utf8&useSSL=true" +
"&socketFactory=" + MySocketFactory.class.getName();
The client did execute my version createSSLSocket() and return a Socket object. However, I got the following Exceptions after continuing the execution:
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException:
Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
javax.net.ssl.SSLException:
Unrecognized SSL message, plaintext connection?
I'm sure the MySQL was up and running, the address and port passed to createSSLSocket() were correct. Could anyone help? The client has to communicate to 2 sites at the same time: an HTTPS web server and a self-signed MySQL server.