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H2 Database connection timeout with new computer

I'm using two H2 databases in my Java projects. Recently, I changed my computer and since then I have no problem with connecting to one of those databases using my Java code but problems with the other one. It's exactly the same code (up to PATH_TO_DATABASE) I use to start the connection:
import java.sql.DriverManager;
import java.sql.SQLException;
public class DatabaseConfig {
private static java.sql.Connection connection;
public static void init() {
if (connection == null) {
try {
connection = DriverManager.getConnection("jdbc:h2:tcp://192.168.178.50:9092/C:/Users/PATH_TO_DATABASE", "USER", "PW");
} catch (SQLException e) {
System.err.println("SQLException");
e.printStackTrace();
System.exit(0);
}
}
}
[...]
}
This is the stack trace I get:
SQLException
org.h2.jdbc.JdbcSQLException: Connection is broken: "java.net.SocketTimeoutException: connect timed out: 192.168.178.21:9092" [90067-196]
at org.h2.message.DbException.getJdbcSQLException(DbException.java:345)
at org.h2.message.DbException.get(DbException.java:168)
at org.h2.engine.SessionRemote.connectServer(SessionRemote.java:457)
at org.h2.engine.SessionRemote.connectEmbeddedOrServer(SessionRemote.java:334)
at org.h2.jdbc.JdbcConnection.<init>(JdbcConnection.java:116)
at org.h2.jdbc.JdbcConnection.<init>(JdbcConnection.java:100)
at org.h2.Driver.connect(Driver.java:69)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at data.DatabaseConfig.init(DatabaseConfig.java:20)
...
Caused by: java.net.SocketTimeoutException: connect timed out
at java.net.DualStackPlainSocketImpl.waitForConnect(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.h2.util.NetUtils.createSocket(NetUtils.java:103)
at org.h2.util.NetUtils.createSocket(NetUtils.java:83)
at org.h2.engine.SessionRemote.initTransfer(SessionRemote.java:115)
at org.h2.engine.SessionRemote.connectServer(SessionRemote.java:453)
... 8 more
Using the web interface I can connect to both databases easily.
I'm a little bit lost here since I can't figure out what's going wrong with one of the databases. The strange thing is that everything works fine with the other database.
EDIT: I just realized that the IP address in the error message is different from the one in the code (192.168.178.21:9092 vs. 192.168.178.50:9092). Maybe this is th ereason of the error. The one in the code is the correct IP address. Why do I get a different one in the error message? Is that the reason of my problem?

If it's a remote connection, do an ipconfig to find out if the 192.168.x.x. address is changed.
If it's a local connection, you can simplify your URL as
jdbc:h2:~/PATH_TO_DATABASE

I just solved the problem (it was kind of my stupidity): The project couldn't build on the new computer because the H2 jar was not properly included in the build path. That's why eclipse called all the time the old .class file and hence tried to connect to the old computer (192.168.178.21:9092) instead to the new one (192.168.178.50:9092). I didn't realize that eclipse didn't compile and was executing old stuff.

java.sql.SQLException: The Network Adapter could not establish the connection

I am face with a problem this day. I have tried to make a shakeout with my database, which is Oracle 11g installed localy on my pc and using JAR Ojdbc6, to connect on it using few line of java code. But anything what I have tried wasn't worked.
Tried :
- Connection with SQL DEV =>is worked
- Start Listener => All ready started
- Try to change the Ip from the URL => still can't connect
I see that is a generic error, but no one has a good response. I can't understand why with SQL DEV is working but with Eclipse not.
I Hope that someone can' help me,
This is my code :
package testare;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.SQLException;
public class oracle {
public static void main(String[] argv) {
System.out.println("-------- Oracle JDBC Connection Testing ------");
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
} catch (ClassNotFoundException e) {
System.out.println("Where is your Oracle JDBC Driver?");
e.printStackTrace();
return;
}
System.out.println("Oracle JDBC Driver Registered!");
Connection connection = null;
try {
connection = DriverManager.getConnection(
"jdbc:oracle:thin:#localhost:1521/orcl", "hr","hr");
} catch (SQLException e) {
System.out.println("Connection Failed! Check output console");
e.printStackTrace();
return;
}
if (connection != null) {
System.out.println("You made it, take control your database now!");
} else {
System.out.println("Failed to make connection!");
}
}
}
This is my Error:
-------- Oracle JDBC Connection Testing ------
Oracle JDBC Driver Registered!
Connection Failed! Check output console
java.sql.SQLException: The Network Adapter could not establish the connection
at oracle.jdbc.driver.SQLStateMapping.newSQLException(SQLStateMapping.java:70)
at oracle.jdbc.driver.DatabaseError.newSQLException(DatabaseError.java:133)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:199)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:480)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:413)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:508)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:203)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:33)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:510)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at testare.oracle.main(oracle.java:31)
Caused by: oracle.net.ns.NetException: The Network Adapter could not establish the connection
at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:328)
at oracle.net.resolver.AddrResolution.resolveAndExecute(AddrResolution.java:421)
at oracle.net.ns.NSProtocol.establishConnection(NSProtocol.java:630)
at oracle.net.ns.NSProtocol.connect(NSProtocol.java:329)
at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:966)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:292)
... 7 more
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 oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:127)
at oracle.net.nt.ConnOption.connect(ConnOption.java:126)
at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:306)
... 12 more

I think the correct URL would be jdbc:oracle:thin:#localhost:1521:orcl

NameNotFoundException doing JNDI lookup to remote EJB in production JBoss (works locally)

An application (e.g app.EAR) is deployed to a JBoss in my own machine and works fine. When I deploy it to a remote JBoss it is deployed, but when I try to access a functionality that needs a JNDI lookup to a remote EJB I get NameNotFoundException. So, it seems that it was unable to find the requested service. How come? If it works locally?
The dependency with the remote EJB interface is in the lib folder inside the EAR and of course is annotated with #Remote. The JBoss is exactly the same as the production one (I copied the whole JBoss from production to my machine to check if there is any configuration missing).
My lookup code is like this:
private Object lookup(String resourceName, String loginData) {
if (isPropagateUserCredentials() && (loginData == null || loginData.trim().equals(""))) {
throw new MyInfraConfigException("somemessage");
}
Properties envProperties = new Properties();
envProperties.putAll(this.jndiProperties);
if (loginData != null && !loginData.equals("")) {
envProperties.put(Context.SECURITY_PRINCIPAL, loginData);
envProperties.remove(Context.SECURITY_CREDENTIALS);
}
Context context = null;
try {
context = new InitialContext(envProperties);
return context.lookup(resourceName);
} catch (NameNotFoundException e){
String message = "Resource "+resourceName+" not found.";
LoggerFactory.getInstance(this.getClass().getName()).error(message, e);
throw new com.mypackage.NameNotFoundException(message, e);
} catch (NamingException e) {
String message = "Failed to find resource with JNDI: "+e.getMessage();
LoggerFactory.getInstance(this.getClass().getName()).error(message, e);
throw new com.mypackage.NamingException(message, e);
} finally{
if(context!=null){
try {
context.close();
} catch (NamingException e) {
e.printStackTrace();
}
}
}
}
The resourceName is ExternalResource.
The stacktrace is below:
29/06/2015 10:30:43 oracle.j2ee.clustering.ClusteringMessages warningInOpmnGetServers
AVISO: Error in obtaining server list from OPMN on host XX.XXX.XXX.XXX:XXXX. Please verify that OPMN is running.
javax.naming.NameNotFoundException: ExternalResource not found
at com.evermind.server.rmi.RMIClientContext.lookup(RMIClientContext.java:60)
at javax.naming.InitialContext.lookup(InitialContext.java:392)
at br.teste.TestaJNDI.main(TestaJNDI.java:33)
Any clues?
UPDATE
Made an external simple java application in order to try to connect to the server and understand the cause of the problem. In fact, the problem is that I am getting a connection timeout:
javax.naming.CommunicationException: Connection timed out [Root exception is java.net.ConnectException: Connection timed out]
at com.evermind.server.rmi.RMIClient.lookup(RMIClient.java:311)
at com.evermind.server.rmi.RMIClientContext.lookup(RMIClientContext.java:59)
at javax.naming.InitialContext.lookup(Unknown Source)
at br.teste.TestaJNDI.listaUFs(TestaJNDI.java:55)
at br.teste.TestaJNDI.main(TestaJNDI.java:37)
Caused by: java.net.ConnectException: Connection timed out
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 com.evermind.server.rmi.RMIClientConnection.createSocket(RMIClientConnection.java:802)
at oracle.oc4j.rmi.ClientSocketRmiTransport.createNetworkConnection(ClientSocketRmiTransport.java:59)
at oracle.oc4j.rmi.ClientRmiTransport.connectToServer(ClientRmiTransport.java:75)
at oracle.oc4j.rmi.ClientSocketRmiTransport.connectToServer(ClientSocketRmiTransport.java:69)
at com.evermind.server.rmi.RMIClientConnection.connect(RMIClientConnection.java:765)
at com.evermind.server.rmi.RMIClientConnection.sendLookupRequest(RMIClientConnection.java:247)
at com.evermind.server.rmi.RMIClientConnection.lookup(RMIClientConnection.java:231)
at com.evermind.server.rmi.RMIClient.lookup(RMIClient.java:302)
... 4 more

This might be a network communication issue. I would check if the server does allow for communication on the remoting ports. Try telnet the server, if its configured to accept these requests:
telnet <server> <port>
If using default ports, I think this should be 4447. If this connection fails then answer the following:
1. Is there no firewall that might be blocking this communication.
2. Are you using the correct port as configured by your production server.
There could really be other reasons for the fail, but that would be a starting point.

I found a net connection error while using localhost in jdbc

I wrote this program to connect with my database which is on the same computer but i found a net connection error each time. com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
import java.sql.*;
public class Demo {
public static void main(String[] args) {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection connection = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/db","username","pwd");
Statement stmt = connection.createStatement();
String str="SHOW TABLES";
ResultSet resultSet=stmt.executeQuery(str);
while (resultSet.next()) {
System.out.println(resultSet.getString(1));
}
}catch(Exception e){
e.printStackTrace();
}
}
}
My Stacktrace is:-
com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.net.ConnectException
MESSAGE: Connection refused: connect
STACKTRACE:
java.net.ConnectException: Connection refused: 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 com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:271)
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771)
at com.mysql.jdbc.Connection.<init>(Connection.java:1555)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at Demo.main(Demo.java:8)
** END NESTED EXCEPTION **
Last packet sent to the server was 0 ms ago.
at com.mysql.jdbc.Connection.createNewIO(Connection.java:2847)
at com.mysql.jdbc.Connection.<init>(Connection.java:1555)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at Demo.main(Demo.java:8)

Try this:
DriverManager.getConnection("jdbc:mysql://localhost:3306/dbname","username","password");
If this is not sorted out go to where you installed Mysql and open MySQL Notifier and check server is running or not if not start it and then try executing your program.

This error was mainly due to Mysql server not reachable or not running. Check with below points:
1. Check your DB Connection whether MYSQL is up and running.
2. Check if you are able to connect from command prompt
3. Restart the mysql server and try again.

Database not found error when connecting to Derby network server

I'm having problems initializing my javadb network server and setting a connection to it. It's a JavaFX program.
This is what I have so far:
try {
Class.forName("org.apache.derby.jdbc.ClientDriver").newInstance();
javadbserver = new NetworkServerControl();
javadbserver.start(null);
} catch (ClassNotFoundException e) {
Logger.getLogger(MainGuiController.class.getName()).log(Level.SEVERE, null, ex);
System.out.println("Where is your JavaDB embedded Driver?");
return;
}
String dbName = "mydb";
String dbUser = "auser";
String dbPass = "password";
PreparedStatement prepstmt;
try {
this.conn = DriverManager.getConnection("jdbc:derby://localhost:1527/mydb;user=auser;password=password");
System.out.println("Went through!");
} catch (SQLException ex) {
Logger.getLogger(MainGuiController.class.getName()).log(Level.SEVERE, null, ex);
}
I always catch the second exception.
If I right click on the javadb service in netbeans and choose connect, everything runs smoothly. [Actually it'd be nice to know what code or program java runs in the background when I select that]
In my projects list under libraries I see derby.jar, derbyclient.jar and derbynet.jar
What am I doing wrong? Please help!
Here's the error I get
java.sql.SQLNonTransientConnectionException: The connection was refused because the database mydb was not found.
at org.apache.derby.client.am.SQLExceptionFactory40.getSQLException(Unknown Source)
at org.apache.derby.client.am.SqlException.getSQLException(Unknown Source)
at org.apache.derby.jdbc.ClientDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(DriverManager.java:579)
at java.sql.DriverManager.getConnection(DriverManager.java:243)
at mydb.MainGuiController.initialize(MainGuiController.java:105)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2152)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2028)
at mydb.mydb.start(mydb.java:37)
at com.sun.javafx.application.LauncherImpl$5.run(LauncherImpl.java:319)
at com.sun.javafx.application.PlatformImpl$5.run(PlatformImpl.java:215)
at com.sun.javafx.application.PlatformImpl$4$1.run(PlatformImpl.java:179)
at com.sun.javafx.application.PlatformImpl$4$1.run(PlatformImpl.java:176)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl$4.run(PlatformImpl.java:176)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
at com.sun.glass.ui.win.WinApplication$3$1.run(WinApplication.java:73)
at java.lang.Thread.run(Thread.java:722)
Caused by: org.apache.derby.client.am.DisconnectException: The connection was refused because the database mydb was not found.
at org.apache.derby.client.net.NetConnectionReply.parseRDBNFNRM(Unknown Source)
at org.apache.derby.client.net.NetConnectionReply.parseAccessRdbError(Unknown Source)
at org.apache.derby.client.net.NetConnectionReply.parseACCRDBreply(Unknown Source)
at org.apache.derby.client.net.NetConnectionReply.readAccessDatabase(Unknown Source)
at org.apache.derby.client.net.NetConnection.readSecurityCheckAndAccessRdb(Unknown Source)
at org.apache.derby.client.net.NetConnection.flowSecurityCheckAndAccessRdb(Unknown Source)
at org.apache.derby.client.net.NetConnection.flowUSRIDPWDconnect(Unknown Source)
at org.apache.derby.client.net.NetConnection.flowConnect(Unknown Source)
at org.apache.derby.client.net.NetConnection.<init>(Unknown Source)
at org.apache.derby.client.net.NetConnection40.<init>(Unknown Source)
at org.apache.derby.client.net.ClientJDBCObjectFactoryImpl40.newNetConnection(Unknown Source)

By the JDBC url, it's looks like you're trying to connect to a Derby server vs. an embedded instance. If you are trying to connect to a server instance, here are some considerations:
did you start the server yourself, did mydb already exists?
if not, did you pass in the correct params to create (e.g. ;create=true)
example: jdbc:derby://localhost:1527/dbname;create=true
if mydb did exists, are you pointing the server to the correct location?
also, depending on what was used to start derby (e.g. embedded vs network driver) default database locations are different as well. You can read about it here
Basically the exception you're getting is that Derby's saying it can't find your database - it's basically a path issue.

If you're using netbeans, you should fix this by going into the connection properties and adding a property. Under "property" type "create" and under "value" type "true".