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Trying to connect to RMI Registry but getting java.net.ConnectException: Connection refused: connect

I have two computers. On one of them, is running an RMI Registry - which was created from this code alone:
package main;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.util.Scanner;
public class TheRegistry{
public static void main(String[] args) {
try {
Registry reg = LocateRegistry.createRegistry(2020);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally{
System.out.println("Registry Created");
Scanner input = new Scanner(System.in);
input.nextInt();
System.exit(0);
}
}
}
The other computer has a server that is trying to register an Object on this registry, however, it gets an exception. Here is the code for the server:
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.UnicastRemoteObject;
import java.rmi.*;
public class TextScramblerServer implements TextScramblerInterface
{
private static Remote obj;
// main method to export
#Override //Return input text as-is.
public String testInputText(String inputText) {
return "Your input text is: " + inputText;
}
#Override //Return the string reversed.
public String reverse(String inputText) {
String reversedInput = "";
for(int i=0; i<inputText.length();i++)
{
reversedInput=reversedInput+inputText.charAt((inputText.length()-1)-i);
}
return "Result: "+reversedInput;
}
#Override //Return the string scrambled.
public String scramble(String inputText) {
String scrambledInput="";
for(int i=0; i<inputText.length();i++)
{
if(i%2==0)
{
scrambledInput=scrambledInput+inputText.charAt(i);
}
else
{
scrambledInput=inputText.charAt(i)+scrambledInput;
}
}
return "Result: "+scrambledInput;
}
public void exportServer() throws Exception {
System.setSecurityManager(new RMISecurityManager());
obj = UnicastRemoteObject.exportObject(this, 2022);
Registry registry = LocateRegistry.getRegistry("132.205.94.50", 2020);
registry.bind("test", obj);
}
public static void main(String[] args) {
try {
(new TextScramblerServer()).exportServer();
System.out.println("Server is up and running");
}
catch(Exception e){
e.printStackTrace();
try {
UnicastRemoteObject.unexportObject(obj, true); //close port
} catch (NoSuchObjectException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
}
}
I keep getting the error:
java.rmi.ConnectException: Connection refused to host: 132.205.94.50; nested exception is:
java.net.ConnectException: Connection refused: connect
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(Unknown Source)
at sun.rmi.transport.tcp.TCPChannel.createConnection(Unknown Source)
at sun.rmi.transport.tcp.TCPChannel.newConnection(Unknown Source)
at sun.rmi.server.UnicastRef.newCall(Unknown Source)
at sun.rmi.registry.RegistryImpl_Stub.bind(Unknown Source)
at TextScramblerServer.exportServer(TextScramblerServer.java:57)
at TextScramblerServer.main(TextScramblerServer.java:62)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(Unknown Source)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(Unknown Source)
... 7 more
java.rmi.NoSuchObjectException: object not exported
at sun.rmi.transport.ObjectTable.unexportObject(Unknown Source)
at java.rmi.server.UnicastRemoteObject.unexportObject(Unknown Source)
at TextScramblerServer.main(TextScramblerServer.java:68)
I can't figure out why this is happening. I think I've tried everything

I ran your code and it worked for me after configuring the security policy.
Your ConnectionRefused exception means that the underlying TCP connection cannot be established. It's network issue, not an RMI issue.
Try running both the server and registry on the same host, and use localhost as the hostname. If it works, the problem is likely a firewall issue between the two hosts.
You can do a simple test of a TCP connection to the specific port using telnet. If the port isn't listening, telnet will give you a similar connection refused message. If the port is listening, you'll get something like this on the terminal:
Connected to localhost.
Escape character is '^]'.
Control-C to get out of the session.
The specific telnet output may vary based on your OS, but they are all about the same.
If it is a firewall issue, you'll have to open up the ports. How to do that depends on OS, but it's easy to find.

Either your Registry has been garbage-collected, you got the IP address wrong, or it is a public IP address and you haven't configured port forwarding.
You need to store the Registry reference in a static object to overcome garbage collection, although what the point of that program is when rmiregistry.exe already exists escapes me completely.
You're barking up the wrong tree anyway. You can only bind to an RMI Registry that is running in the local host. There is therefore never any need to use a Registry hostname other than "localhost" when binding or unbinding.
The reason you got the NoSuchObjectException is that you are trying to unexport the stub, which is referred to by obj, which is the result of UnicastRemoteObject.exportObject(), which returns the stub. See the Javadoc. You need to save the result of new TextScramblerServer() and unexport that.

Derby DB server start by java code

I do not want to install a database server on target machine. It is possible that we can simply ship a jar file with the database embedded in it, and not worry about installing a database server separately?
I created one application in netbeans using derby and it is working fine in my pc but when i am running on other machine it is giving me an Exception
My code is
System.setProperty("derby.drda.startNetworkServer", "true");
try {
NetworkServerControl serverControl = new NetworkServerControl();
serverControl.start(new PrintWriter(System.out, true));
} catch (Exception e) {
e.printStackTrace();
}
For connection i wrote this code
public static Connection getderbyConnection() throws ClassNotFoundException, SQLException
{
String url = "jdbc:derby://localhost:1527/XLS_Uniquewordlist;create=true";
String user = "root";
String password = "mantra";
Class.forName("org.apache.derby.jdbc.ClientDriver");
return (Connection) DriverManager.getConnection(url, user, password);
}
I am getting this exception
Exception in thread "DRDAConnThread_2" java.lang.NoSuchMethodError:
org.apache.derby.iapi.jdbc.EnginePreparedStatement.getVersionCounter()J
at org.apache.derby.impl.drda.DRDAStatement.prepare(Unknown Source)
at org.apache.derby.impl.drda.DRDAStatement.explicitPrepare(Unknown
Source)
at org.apache.derby.impl.drda.DRDAConnThread.parsePRPSQLSTT(Unknown
Source)
at org.apache.derby.impl.drda.DRDAConnThread.processCommands(Unknown
Source)
at org.apache.derby.impl.drda.DRDAConnThread.run(Unknown Source)
May 12, 2015 5:17:59 PM xls_parser.Main_panel btnokActionPerformed
SEVERE: null
java.sql.SQLSyntaxErrorException: DERBY SQL error: SQLCODE: -20001, SQLSTATE: 42X05, SQLERRMC: APP.UNIQUEWORDLIST42X05
at org.apache.derby.client.am.SQLExceptionFactory40.getSQLException(Unknown
Source)
at org.apache.derby.client.am.SqlException.getSQLException(Unknown
Source)
at org.apache.derby.client.am.Connection.prepareStatement(Unknown Source)

RMI Client java.rmi.ConnectException

I have some problems to connect the remote object for client class. I get java.rmi.ConnectException when I run following client class.
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
public class Client {
/**
* Declare Payment Stub object.
*/
private static Payment stub = null;
private Client() {
}
public static void main(String[] args) {
double principal = 80000;
double annualInterest = .065;
int years = 15;
/**
* Try to connect the server and look up the
* defined stub.
*/
try {
Registry reg = LocateRegistry.getRegistry("localhost");
stub = (Payment) reg.lookup("Mortgage");
} catch (Exception e) {
System.err.println("Client exception thrown: " + e.toString());
e.printStackTrace();
}
}
The server side is following:
import java.rmi.registry.Registry;
import java.rmi.registry.LocateRegistry;
import java.rmi.server.UnicastRemoteObject;
public class Server {
public Server() {
}
public static void main(String args[]) {
try {
PaymentImpl robj = new PaymentImpl();
Payment stub = (Payment) UnicastRemoteObject.exportObject(robj, 9260);
Registry registry = LocateRegistry.createRegistry(9260);
registry.bind("Mortgage", stub);
System.out.println("Mortgage Server is ready to listen... ");
} catch (Exception e) {
System.err.println("Server exception thrown: " + e.toString());
e.printStackTrace();
}
}
}
The exception when I run Client class is:
Client exception thrown: java.rmi.ConnectException: Connection refused to host: localhost; nested exception is:
java.net.ConnectException: Connection refused: connect
java.rmi.ConnectException: Connection refused to host: localhost; nested exception is:
java.net.ConnectException: Connection refused: connect
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(Unknown Source)
at sun.rmi.transport.tcp.TCPChannel.createConnection(Unknown Source)
at sun.rmi.transport.tcp.TCPChannel.newConnection(Unknown Source)
at sun.rmi.server.UnicastRef.newCall(Unknown Source)
at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source)
at Client.main(Client.java:24)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(Unknown Source)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(Unknown Source)
... 6 more

The issue was with the port number at client side. Specify the port number also while getting the Registry.
Java Doc for LocateRegistry.getRegistry("localhost") says:
Returns a reference to the the remote object Registry for the local host on the default registry port of 1099.
Try
Client.java (specify the port no)
Registry reg = LocateRegistry.getRegistry("localhost",9260);
or
Server.java (use default port no)
Registry registry = LocateRegistry.createRegistry(1099);

Java FTPS Problems

Still unanswered. Any and all help is appreciated!
I am using Apache Commons-Net3.1 and trying to get the FTPS working. When I try to connect, I am getting the following errors in the console :
---EDIT: CODE AND ERRORS UPDATED---
java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at org.apache.commons.net.SocketClient.connect(SocketClient.java:171)
at org.apache.commons.net.SocketClient.connect(SocketClient.java:192)
at org.apache.commons.net.SocketClient.connect(SocketClient.java:285)
I am sure I am just not setting up it up right. Here is my code. Any point in the right direction would be greatly appreciated. (I am trying to connect via port 990 by the way). The code errors at the line "client.connect(ftpHost);"
import org.apache.commons.net.ftp.FTPSClient;
import java.io.IOException;
import java.io.FileOutputStream;
public class MyFTP {
public void downloadFTP(){
FTPSClient client = new FTPSClient(false);
FileOutputStream fos = null;
client.setTrustManager(TrustManagerUtils.getAcceptAllTrustManager());
try {
client.connect(ftpHost);
client.enterLocalPassiveMode();
client.login(ftpUser, ftpPassword);
String filename = "liveGUIfile.txt";
fos = new FileOutputStream(filename);
client.retrieveFile("/root/Desktop/" + filename, fos);
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (fos != null) {
fos.close();
}
client.disconnect();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

FTPS may be explicit or implicit, you use explicit:
FTPSClient client = new FTPSClient(false);
But explicit one usually uses 21 port, like FTP does, and implicit one uses 990 port. So try to connect to 21 port or to use new FTPSClient(true)

javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?
That says it all. Plaintext connection. You are connecting to an FTP server, not an FTPS server. It's right there in the error message.

Java RMI cannot connect to host from external client

I've been using RMI in this project for a while. I've gotten the client program to connect (amongst other things) to the server when running it over my LAN, however when running it over the internet I'm running into the following exception:
java.rmi.ConnectException: Connection refused to host: (private IP of host machine); nested exception is:
java.net.ConnectException: Connection timed out: connect
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(Unknown Source)
at sun.rmi.transport.tcp.TCPChannel.createConnection(Unknown Source)
at sun.rmi.transport.tcp.TCPChannel.newConnection(Unknown Source)
at sun.rmi.server.UnicastRef.invoke(Unknown Source)
at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(Unknown Source)
at java.rmi.server.RemoteObjectInvocationHandler.invoke(Unknown Source)
at $Proxy1.ping(Unknown Source)
at client.Launcher$PingLabel.runPing(Launcher.java:366)
at client.Launcher$PingLabel.<init>(Launcher.java:353)
at client.Launcher.setupContentPane(Launcher.java:112)
at client.Launcher.<init>(Launcher.java:99)
at client.Launcher.main(Launcher.java:59)
Caused by: java.net.ConnectException: Connection timed out: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(Unknown Source)
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(Unknown Source)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(Unknown Source)
... 12 more
This error is remeniscent of my early implementation of RMI and I can obtain the error verbatum if I run the client locally without the server program running as well. To me Connection Timed Out means a problem with the server's response.
Here's the client initiation:
public static void main(String[] args)
{
try
{
String host = "<WAN IP>";
Registry registry = LocateRegistry.getRegistry(host, 1099);
Login lstub = (Login) registry.lookup("Login Server");
Information istub = (Information) registry.lookup("Game Server");
new Launcher(istub, lstub);
}
catch (RemoteException e)
{
System.err.println("Client exception: " + e.toString());
e.printStackTrace();
}
catch (NotBoundException e)
{
System.err.println("Client exception: " + e.toString());
e.printStackTrace();
}
}
Interestingly enough no Remote Exception is thrown here.
Here's the server initiation:
public static void main(String args[])
{
try
{
GameServer gobj = new GameServer();
Information gstub = (Information) UnicastRemoteObject.exportObject(
gobj, 1099);
Registry registry = LocateRegistry.createRegistry(1099);
registry.bind("Game Server", gstub);
LoginServer lobj = new LoginServer(gobj);
Login lstub = (Login) UnicastRemoteObject.exportObject(lobj, 7099);
// Bind the remote object's stub in the registry
registry.bind("Login Server", lstub);
System.out.println("Server ready");
}
catch (Exception e)
{
System.err.println("Server exception: " + e.toString());
e.printStackTrace();
}
}
Bad practice with the catch(Exception e) I know but bear with me.
Up to this stage I know it works fine over the LAN, here's where the exception occurs over the WAN and is the first place a method in the server is called:
private class PingLabel extends JLabel
{
private static final long serialVersionUID = 1L;
public PingLabel()
{
super("");
runPing();
}
public void setText(String text)
{
super.setText("Ping: " + text + "ms");
}
public void runPing()
{
try
{
PingThread pt = new PingThread();
gameServer.ping();
pt.setRecieved(true);
setText("" + pt.getTime());
}
catch (RemoteException e)
{
e.printStackTrace();
}
}
}
That's a label placed on the launcher as a ping test. the method ping(), in gameserver does nothing, as in is a null method.
It's worth noting also that ports 1099 and 7099 are forwarded to the server machine (which should be obvious from the stack trace).
Can anyone see anyting I'm missing/doing wrong? If you need any more information just ask.
EDIT: I'm practically certain the problem has nothing to do with my router settings. When disabling my port forwarding settings I get a slightly different error:
Client exception: java.rmi.ConnectException: Connection refused to host: (-WAN IP NOT LOCAL IP-);
but it appears both on the machine locally connected to the server and on the remote machine.
In addition, I got it to work seamlessly when connecting the server straight tho the modem (cutting out the router. I can only conclude the problem is in my router's settings but can't see where (I've checked and double checked the port forwarding page). That's the only answer i can come up with.

Are you using NAT (Network Address Translation)? This is the typical case if your LAN uses non-routable address behind a router (like 10.x or 192.169.x etc).
If this is the case, you need to specify the public IP of the server with following option,
-Djava.rmi.server.hostname=host_name_or_public_ip