Spring framework integration TCP IP - Client application SSL not working and posting incomplete requests - sockets

Question

I am new to Spring framework. We have a requirement where our application is acting as a client and needs to integrate with another application using TCP. We will be sending them fixed length requests and we will receive response for the same. We have been asked to use the same TCP connection for each request. Using the same open connection, our application will also be receiving heartbeat messages from server application and we do not need to send any response for them.
The request messages that we need to send is header + body where header has message type and length details.
We will be using SSL. When we try to test with SSL, it does not show any exception during getConnection but is not able to receive any heartbeat messages.
When we test without SSL, it is able to send requests and receive response as well as heartbeat messages. But after the first request response, it sends partial request text to server application for subsequent messages which is causing issues and connections are being reset by peer due to unexpected message received at their end.
I have tried many things referring to online documents available but not able to successfully implement the requirement.
Please find below code. Thanks in advance.
public class ClientConfig implements ApplicationEventPublisherAware{
protected String port;
protected String host;
protected String connectionTimeout;
protected String keyStorePath;
protected String trustStorePath;
protected String keyStorePassword;
protected String trustStorePassword;
protected String protocol;
private ApplicationEventPublisher applicationEventPublisher;
#Override
public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
this.applicationEventPublisher = applicationEventPublisher;
}
#Bean
public DefaultTcpNioSSLConnectionSupport connectionSupport() {
if("SSL".equalsIgnoreCase(getProtocol())) {
DefaultTcpSSLContextSupport sslContextSupport =
new DefaultTcpSSLContextSupport(getKeyStorePath(),
getTrustStorePath(), getKeyStorePassword(), getTrustStorePassword());
sslContextSupport.setProtocol(getProtocol());
DefaultTcpNioSSLConnectionSupport tcpNioConnectionSupport =
new DefaultTcpNioSSLConnectionSupport(sslContextSupport);
return tcpNioConnectionSupport;
}
return null;
}
#Bean
public AbstractClientConnectionFactory clientConnectionFactory() {
if(StringUtils.isNullOrEmptyTrim(getHost()) || StringUtils.isNullOrEmptyTrim(getPort())) {
return null;
}
TcpNioClientConnectionFactory tcpNioClientConnectionFactory =
new TcpNioClientConnectionFactory(getHost(), Integer.valueOf(getPort()));
tcpNioClientConnectionFactory.setApplicationEventPublisher(applicationEventPublisher);
tcpNioClientConnectionFactory.setSoKeepAlive(true);
tcpNioClientConnectionFactory.setDeserializer(new CustomSerializerDeserializer());
tcpNioClientConnectionFactory.setSerializer(new CustomSerializerDeserializer());
tcpNioClientConnectionFactory.setLeaveOpen(true);
tcpNioClientConnectionFactory.setSingleUse(false);
if("SSL".equalsIgnoreCase(getProtocol())) {
tcpNioClientConnectionFactory.setSslHandshakeTimeout(60);
tcpNioClientConnectionFactory.setTcpNioConnectionSupport(connectionSupport());
}
return tcpNioClientConnectionFactory;
}
#Bean
public MessageChannel outboundChannel() {
return new DirectChannel();
}
#Bean
public PollableChannel receiverChannel() {
return new QueueChannel();
}
#Bean
#ServiceActivator(inputChannel = "outboundChannel")
public TcpSendingMessageHandler outboundClient
(AbstractClientConnectionFactory clientConnectionFactory) {
TcpSendingMessageHandler outbound = new TcpSendingMessageHandler();
outbound.setConnectionFactory(clientConnectionFactory);
if(!StringUtils.isNullOrEmpty(getConnectionTimeout())) {
long timeout = Long.valueOf(getConnectionTimeout());
outbound.setRetryInterval(TimeUnit.SECONDS.toMillis(timeout));
}
outbound.setClientMode(true);
return outbound;
}
#Bean
public TcpReceivingChannelAdapter inboundClient(TcpNioClientConnectionFactory connectionFactory) {
TcpReceivingChannelAdapter inbound = new TcpReceivingChannelAdapter();
inbound.setConnectionFactory(connectionFactory);
if(!StringUtils.isNullOrEmpty(getConnectionTimeout())) {
long timeout = Long.valueOf(getConnectionTimeout());
inbound.setRetryInterval(TimeUnit.SECONDS.toMillis(timeout));
}
inbound.setOutputChannel(receiverChannel());
inbound.setClientMode(true);
return inbound;
}
}
public class CustomSerializerDeserializer implements Serializer<String>, Deserializer<String> {
#Override
public String deserialize(InputStream inputStream) throws IOException {
int i = 0;
byte[] lenbuf = new byte[8];
String message = null;
while ((i = inputStream.read(lenbuf)) != -1) {
String messageType = new String(lenbuf);
if(messageType.contains(APP_DATA_LEN)){
byte byteResp[] = new byte[RESP_MSG_LEN-8];
inputStream.read(byteResp, 0, RESP_MSG_LEN-8);
String readMsg = new String(byteResp);
message = messageType + readMsg;
}else {
byte byteResp[] = new byte[HANDSHAKE_LEN-8];
inputStream.read(byteResp, 0, HANDSHAKE_LEN-8);
String readMsg = new String(byteResp);
message = messageType + readMsg;
}
}
return message;
}
#Override
public void serialize(String object, OutputStream outputStream) throws IOException {
outputStream.write(object.getBytes());
outputStream.flush();
}
}
#Override
public String sendMessage(String message) {
Message<String> request = MessageBuilder.withPayload(message).build();
DirectChannel outboundChannel = (DirectChannel) applicationContext.getBean(DirectChannel.class);
outboundChannel.send(request);
}
//Below code is being used to open connection
TcpNioClientConnectionFactory cf = (TcpNioClientConnectionFactory) applicationContext.getBean(AbstractClientConnectionFactory.class);
if(cf != null) {
TcpNioConnection conn = (TcpNioConnection) cf.getConnection();
}