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Single JDBC OracleDataSource/HikariCP with primary/backup DB

I'm trying to set up a single connection pool which references our primary database until said becomes unhealthy and after which the pool fails over, filling up against our backup. Until now I've been taking advantage of an undocumented feature of our application server's JNDI datasources which allows me to specify 2 JDBC connection URL strings thusly:
jdbc:oracle:thin:#primary:1521:DB|jdbc:oracle:thin:#backup:1521:DB
I have the following code, no doubt partially cribbed from some Hikari/Spring documentation months ago.
#Bean(name = "dataSource")
public DataSource dataSource() throws SQLException {
String userName = "user";
String password = "pass";
String server = "primary";
String database = "DB";
OracleDataSource ods = new OracleDataSource();
ods.setServerName(server);
ods.setDatabaseName(database);
ods.setNetworkProtocol("tcp");
ods.setUser(userName);
ods.setPassword(password);
ods.setPortNumber(1521);
ods.setDriverType("thin");
HikariConfig hkConfig = new HikariConfig();
hkConfig.setDataSource(ods);
hkConfig.setDataSourceClassName("oracle.jdbc.pool.OracleDataSource");
hkConfig.setPoolName("springHikariRECPool");
hkConfig.setMaximumPoolSize(15);
hkConfig.setMinimumIdle(3);
hkConfig.setMaxLifetime(1800000); // 30 minutes
return new HikariDataSource(hkConfig);
}
My Google-Fu has failed me. Does anyone have any ideas on how to achieve the failover functionality?
Edit - re. #M. Deinum "Remove the construction of the OracleDataSource and just set the url on the HikariConfig."
HikariConfig hkConfig = new HikariConfig();
hkConfig.setUsername(userName);
hkConfig.setPassword(password);
hkConfig.setJdbcUrl("jdbc:oracle:thin:#primary:1521:DB|jdbc:oracle:thin:#backup:1521:DB");
hkConfig.setDataSourceClassName("oracle.jdbc.pool.OracleDataSource");
hkConfig.setPoolName("springHikariRECPool");
hkConfig.setMaximumPoolSize(15);
hkConfig.setMinimumIdle(3);
hkConfig.setMaxLifetime(1800000);
Unfortunately, this yields a fairly long stack, the base of which is this:
Caused by: java.sql.SQLException: Invalid Oracle URL specified: OracleDataSource.makeURL
at oracle.jdbc.pool.OracleDataSource.makeURL(OracleDataSource.java:1277)
at oracle.jdbc.pool.OracleDataSource.getConnection(OracleDataSource.java:185)
at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:356)
at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:199)
at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:444)
at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:515)
Investigation of that here - Hikaricp Oracle connection issue and here - Invalid Oracle URL specified: OracleDataSource.makeURL causes me to add some additional properties.
hkConfig.addDataSourceProperty("portNumber", "1521");
hkConfig.addDataSourceProperty("driverType", "thin");
Which now bombs with:
Caused by: java.net.UnknownHostException: null: Name or service not known
at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:928)
at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323)
at java.net.InetAddress.getAllByName0(InetAddress.java:1276)
at java.net.InetAddress.getAllByName(InetAddress.java:1192)
at java.net.InetAddress.getAllByName(InetAddress.java:1126)
at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:117)
at oracle.net.nt.ConnOption.connect(ConnOption.java:133)
at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:370)
The JDBC URL is no longer being referenced, it would appear. . . and, confirmed - I took the backup connection string out of the URL and reached the same exception with a standard, single server connection. So it appears the ODS demands to be configured as originally done (or mimicked with Properties).
As a last gasp for this method, I tried setting the serverName property to "primary|standby" and, as expected, that blew up as well:
Caused by: java.net.UnknownHostException: primary|backup: Name or service not known
at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:928)
at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323)
at java.net.InetAddress.getAllByName0(InetAddress.java:1276)
at java.net.InetAddress.getAllByName(InetAddress.java:1192)
at java.net.InetAddress.getAllByName(InetAddress.java:1126)
at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:117)
at oracle.net.nt.ConnOption.connect(ConnOption.java:133)
at oracle.net.nt.ConnStrategy.execute(ConnStrategy.java:411)
... 56 more
I have failed to note thus far that I am using ojdbc7.jar.

Use standard way. Support for DataGuard, failover, RAC is native feature of Oracle JDBC drivers.
1st use tnsnames.ora as described here "How to connect JDBC to tns oracle"
2nd use multiple hosts in tnsnames.ora:
DB =
(DESCRIPTION=
(ADDRESS_LIST=
(LOAD_BALANCE=off)
(FAILOVER=ON)
(ADDRESS=(PROTOCOL=TCP)( HOST=primary)(PORT=1521))
(ADDRESS=(PROTOCOL=TCP)( HOST=backup)(PORT=1521)))
(CONNECT_DATA=(SERVICE_NAME=DB)))
Oracle JDBC driver will connect to the host, where database is "OPEN" and the service named "DB" is present.
PS: you can also pass the whole tns connection string to the jdbc driver directly as a parameter.
url="jdbc:oracle:thin:#(DESCRIPTION=
(LOAD_BALANCE=on)
(ADDRESS_LIST=
(ADDRESS=(PROTOCOL=TCP)(HOST=primary)(PORT=1521))
(ADDRESS=(PROTOCOL=TCP)(HOST=secondary)(PORT=1521)))
(CONNECT_DATA=(SERVICE_NAME=DB)))"

Error when accesing MySQL database remotely using public IP

I have a MySQL database. My friend is trying to access it from a different computer using my public IP.
This is the program he used to test the connection:
public class Main {
public static void main(String args[]) {
String url = "jdbc:mysql://IPadresss:3307/javabase";
String username = "bob";
String password = "bob";
Properties properties = new Properties();
properties.setProperty("bob", "bob");
properties.setProperty("bob", "bob");
properties.setProperty("useSSL", "false");
properties.setProperty("autoReconnect", "true");
System.out.println("Connecting database...");
try (Connection connection = DriverManager.getConnection(url, properties)) {
System.out.println("Database connected!");
} catch (SQLException e) {
throw new IllegalStateException("Cannot connect the database!", e);
}
}
}
This is the error my friend, who is the client, gets:
Connecting database...
Exception in thread "main" java.lang.IllegalStateException: Cannot connect the database!
at SQLConnector.Main.main(Main.java:23)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.Util.getInstance(Util.java:408)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:918)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:897)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:886)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860)
at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2163)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2088)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:806)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:410)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:328)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:208)
at SQLConnector.Main.main(Main.java:20)
Caused by: java.sql.SQLException: Access denied for user ''#'Freinds ip' (using password: NO)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3970)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3906)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:873)
at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1710)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1226)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2253)
at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2104)
... 13 more
Please help me find out what is wrong with my method of connecting to the server, I have remotely given privileges to my friend (user "bob").

So, you have the following error:
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure java.net.ConnectException: Connection
refused
This could happen for a variety of reasons, and I'm quoting from this answer
If you get a SQLException: Connection refused or Connection timed out
or a MySQL specific CommunicationsException: Communications link
failure, then it means that the DB isn't reachable at all.
This can have one or more of the following causes:
IP address or hostname in JDBC URL is wrong.
Hostname in JDBC URL is not recognized by local DNS server.
Port number is missing or wrong in JDBC URL. [Assuming the one you mentioned is correct]
DB server is down.
DB server doesn't accept TCP/IP connections.
DB server has run out of connections.
Something in between Java and DB is blocking connections, e.g. a firewall or proxy.
To solve the one or the other, follow the following advice:
Verify and test them with ping.
Refresh DNS or use IP address in JDBC URL instead.
Verify it based on my.cnf of MySQL DB.
Start the DB.
Verify if mysqld is started without the --skip-networking option.
Restart the DB and fix your code accordingly that it closes connections in finally.
Disable firewall and/or configure
firewall/proxy to allow/forward the port.

How to connect to Azure SQL database with jTDS

I try to connect to Azure SQL with:
import java.sql.*;
public class ExampleJTDS {
public static void main(String[] args) {
// Setting.
String connectionUrl = "jdbc:jtds:sqlserver://SERVER.database.windows.net:1433/DATABASE;ssl=off";
String user = "USER#SERVER";
String pass = "PASSWORD";
// Declare the JDBC object.
Connection conn = null;
try {
// Establish the connection.
Class.forName("net.sourceforge.jtds.jdbc.Driver");
conn = DriverManager.getConnection(connectionUrl, user, pass);
}
catch (Exception e) {
e.printStackTrace();
}
}
}
But I am getting:
java.sql.SQLException: I/O Error: DB server closed connection.
at net.sourceforge.jtds.jdbc.TdsCore.nextToken(TdsCore.java:2481)
at net.sourceforge.jtds.jdbc.TdsCore.login(TdsCore.java:632)
at net.sourceforge.jtds.jdbc.JtdsConnection.<init>(JtdsConnection.java:371)
at net.sourceforge.jtds.jdbc.Driver.connect(Driver.java:184)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:247)
at run.ExampleJTDS.main(ExampleJTDS.java:21)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
If I force the encryption by substituting ssl=off with ssl=require, I am getting:
java.sql.SQLException: Network error IOException: Connection reset
at net.sourceforge.jtds.jdbc.JtdsConnection.<init>(JtdsConnection.java:436)
at net.sourceforge.jtds.jdbc.Driver.connect(Driver.java:184)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:247)
at run.ExampleJTDS.main(ExampleJTDS.java:21)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Interestingly, I can connect to the database from the same computer and with the same JDBC driver with SQuirreL SQL (although without SSL - SQuirreL SQL manages to put the credentials into the first TDS packet and Azure accepts that). Hence, the problem should not be in the setting of firewalls.
Metadata:
Server: Azure V12
Driver: jtds-1.3.1
JRE: 1.8.0_72-b15 (from Oracle)
_JAVA_OPTIONS: -Djsse.enableCBCProtection=false
security.provider.1: sun.security.provider.Sun
OS: OS X 10.11.5
SQuirreL SQL: 3.7.1
How can I connect to Azure SQL from Java?

Per my experience, I think the issue was caused by the connection string which is the variable connectionUrl of your code. I have answered your similar question of the SO thread, please see How to connect to Azure SQL with JDBC.
However, using jTDS instead of Microsoft JDBC driver for SQL Server has a little difference, you can refer to a note in the step 3 of the tutorial to know it. As reference, I post the contento of the note here.
Note:
If you are using the JTDS JDBC driver, then you will need to add "ssl=require" to the URL of the connection string and you need to set the following option for the JVM "-Djsse.enableCBCProtection=false". This JVM option disables a fix for a security vulnerability, so make sure you understand what risk is involved before setting this option.
Hope it helps. Any concern, please feel free to let me know.

connection timed out error while deploying spring app

I’m trying to deploy a simple Spring app and getting a “connection timed out ” error. My app tries to take a text input from the user in one jsp, insert that value under username in the db and then display that name in another jsp along with a greeting eg: "hello, "
My environment:
OS: Windows XP professional
Server : Tomcat 6
IDE: Eclipse
DB: MS Access 2007
I am getting the error below:
SEVERE: Context initialization failed
org.springframework.beans.factory.BeanDefinitionStoreException:
IOException parsing XML document from
ServletContext resource
[/WEB-INF/applicationContext.xml];
nested exception is
java.net.ConnectException: Connection
timed out: connect
java.net.ConnectException: Connection
timed out: connect
at java.net.PlainSocketImpl.socketConnect(Native
Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.Socket.connect(Socket.java:520)
at java.net.Socket.connect(Socket.java:470)
at sun.net.NetworkClient.doConnect(NetworkClient.java:157)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:388)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:523)
at sun.net.www.http.HttpClient.(HttpClient.java:231)
at sun.net.www.http.HttpClient.New(HttpClient.java:304)
at sun.net.www.http.HttpClient.New(HttpClient.java:321)
SEVERE: Servlet /SpringExample threw
load() exception
java.net.ConnectException: Connection
timed out: connect
at java.net.PlainSocketImpl.socketConnect(Native
Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.Socket.connect(Socket.java:520)
at java.net.Socket.connect(Socket.java:470)
at sun.net.NetworkClient.doConnect(NetworkClient.java:157)
The code to access the db is as below:
//in the profile.java class
public void setUsername(String username) {
int rowsInserted;
setDataSource(dataSource);
jt = new JdbcTemplate(dataSource);
rowsInserted = jt.update("insert into usernamedb (username) values(?)",new Object[] { username });
System.out.println(rowsInserted);
}
in the profileFormController.java class
protected ModelAndView onSubmit(Object command)
{
Profile profile = (Profile) command;
String greeting = "Hello," + profile.getUsername() + "!";
//System.out.println(greeting);
profile.setUsername(profile.getUsername());
return new ModelAndView("greetingDisplay", "greeting", greeting);
}
To set up the DNS, in the ODBC sources I have set “usernamedb” as a DNS source by the user. I am not able to figure out the root cause for this error.

First I would check to see if your db server is running. If it is, make sure you are trying to connect to it at the right address at the right port number, and if you are giving it the right username and password.
If all of those seem to be working you may also need to check that your db server will accept connections from the your address.

In case, any one is still looking for a resolution, take a look at the DTD definition in your /WEB-INF/applicationContext.xml including the dtd version
If you can't find anything wrong, try moving to the XML Schema style of configuration. Please see http://docs.spring.io/spring/docs/current/spring-framework-reference/html/xsd-config.html#xsd-config-body

Create a jTDS connection string

my sql server instance name is MYPC\SQLEXPRESS and I'm trying to create a jTDS connection string to connect to the database 'Blog'. Can anyone please help me accomplish that?
I'm trying to do like this:
DriverManager.getConnection("jdbc:jtds:sqlserver://127.0.0.1:1433/Blog", "user", "password");
and I get this:
java.sql.SQLException: Network error IOException: Connection refused: connect
at net.sourceforge.jtds.jdbc.ConnectionJDBC2.<init>(ConnectionJDBC2.java:395)
at net.sourceforge.jtds.jdbc.ConnectionJDBC3.<init>(ConnectionJDBC3.java:50)
at net.sourceforge.jtds.jdbc.Driver.connect(Driver.java:184)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at SqlConnection.Connect(SqlConnection.java:19)
at main.main(main.java:11)
Caused by: 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 sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.sourceforge.jtds.jdbc.SharedSocket.createSocketForJDBC3(SharedSocket.java:305)
at net.sourceforge.jtds.jdbc.SharedSocket.<init>(SharedSocket.java:255)
at net.sourceforge.jtds.jdbc.ConnectionJDBC2.<init>(ConnectionJDBC2.java:323)
... 6 more

As detailed in the jTDS Frequenlty Asked Questions, the URL format for jTDS is:
jdbc:jtds:<server_type>://<server>[:<port>][/<database>][;<property>=<value>[;...]]
So, to connect to a database called "Blog" hosted by a MS SQL Server running on MYPC, you may end up with something like this:
jdbc:jtds:sqlserver://MYPC:1433/Blog;instance=SQLEXPRESS;user=sa;password=s3cr3t
Or, if you prefer to use getConnection(url, "sa", "s3cr3t"):
jdbc:jtds:sqlserver://MYPC:1433/Blog;instance=SQLEXPRESS
EDIT: Regarding your Connection refused error, double check that you're running SQL Server on port 1433, that the service is running and that you don't have a firewall blocking incoming connections.

Really, really, really check if the TCP/IP protocol is enabled in your local SQLEXPRESS instance.
Follow these steps to make sure:
Open "Sql Server Configuration Manager" in "Start Menu\Programs\Microsoft SQL Server 2012\Configuration Tools\"
Expand "SQL Server Network Configuration"
Go in "Protocols for SQLEXPRESS"
Enable TCP/IP
If you have any problem, check this blog post for details, as it contains screenshots and much more info.
Also check if the "SQL Server Browser" windows service is activated and running:
Go to Control Panel -> Administrative Tools -> Services
Open "SQL Server Browser" service and enable it (make it manual or automatic, depends on your needs)
Start it.
That's it.
After I installed a fresh local SQLExpress, all I had to do was to enable TCP/IP and start the SQL Server Browser service.
Below a code I use to test the SQLEXPRESS local connection. Of course, you should change the IP, DatabaseName and user/password as needed.:
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
public class JtdsSqlExpressInstanceConnect {
public static void main(String[] args) throws SQLException {
Connection conn = null;
ResultSet rs = null;
String url = "jdbc:jtds:sqlserver://127.0.0.1;instance=SQLEXPRESS;DatabaseName=master";
String driver = "net.sourceforge.jtds.jdbc.Driver";
String userName = "user";
String password = "password";
try {
Class.forName(driver);
conn = DriverManager.getConnection(url, userName, password);
System.out.println("Connected to the database!!! Getting table list...");
DatabaseMetaData dbm = conn.getMetaData();
rs = dbm.getTables(null, null, "%", new String[] { "TABLE" });
while (rs.next()) { System.out.println(rs.getString("TABLE_NAME")); }
} catch (Exception e) {
e.printStackTrace();
} finally {
conn.close();
rs.close();
}
}
}
And if you use Maven, add this to your pom.xml:
<dependency>
<groupId>net.sourceforge.jtds</groupId>
<artifactId>jtds</artifactId>
<version>1.2.4</version>
</dependency>

jdbc:jtds:sqlserver://x.x.x.x/database replacing x.x.x.x with the IP or hostname of your SQL Server machine.
jdbc:jtds:sqlserver://MYPC/Blog;instance=SQLEXPRESS
or
jdbc:jtds:sqlserver://MYPC:1433/Blog;instance=SQLEXPRESS
If you are wanting to set the username and password in the connection string too instead of against a connection object separately:
jdbc:jtds:sqlserver://MYPC/Blog;instance=SQLEXPRESS;user=foo;password=bar
(Updated my incorrect information and add reference to the instance syntax)

A shot in the dark, but
From the looks of your error message, it seems that either the sqlserver instance is not running on port 1433 or something is blocking the requests to that port

SQLServer runs the default instance over port 1433. If you specify the port as port 1433, SQLServer will only look for the default instance. The name of the default instance was created at setup and usually is SQLEXPRESSxxx_xx_ENU.
The instance name also matches the folder name created in Program Files -> Microsoft SQL Server. So if you look there and see one folder named SQLEXPRESSxxx_xx_ENU it is the default instance.
Folders named MSSQL12.myInstanceName (for SQLServer 2012) are named instances in SQL Server and are not accessed via port 1433.
So if your program is accessing a default instance in the database, specify port 1433, and you may not need to specify the instance name.
If your program is accessing a named instance (not the default instance) in the database DO NOT specify the port but you must specify the instance name.
I hope this clarifies some of the confusion emanating from the errors above.