Develop Reference

Java issue within connection to Microsoft SQL Server

How can I connect to Microsoft SQL Server from my java code?
Code:
public class insert {
public static void main(String[] args) {
try {
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
String url = "jdbc:microsoft:sqlserver://LENOVO-PC\\SQLEXPRESS;DatabaseName=dbtest";
Connection connection = DriverManager.getConnection(url , "sa" , "Aa123456");
Statement st = connection.createStatement();
st.executeUpdate("INSERT INTO [dbo].[table] VALUES ('come')");
}
catch (ClassNotFoundException e)
{
e.printStackTrace();
System.exit(1);
}
catch (SQLException e)
{
e.printStackTrace();
System.exit(2);
}
}
}
Error:
java.lang.ClassNotFoundException: com.microsoft.jdbc.sqlserver.SQLServerDriver
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at insert.main(insert.java:12)
Microsoft SQL Server name is: LENOVO-PC\SQLEXPRESS
and sqljdbc.jar is already added to the referenced libraries.

The class name com.microsoft.jdbc.sqlserver.SQLServerDriver you're trying to load is from a very old version of the Microsoft SQL Server 2000 version of the driver. Around 2005, Microsoft changed this to com.microsoft.sqlserver.jdbc.SQLServerDriver (notice the switch in order between jdbc and sqlserver). At that time, they also changed the driver URL prefix from jdbc:microsoft:sqlserver: to jdbc:sqlserver:.
In other words, you need to:
Use Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver") (optional, driver will be loaded automatically)
Change your URL to jdbc:sqlserver://LENOVO-PC\\SQLEXPRESS;databaseName=dbtest (note the prefix change and DatabaseName -> databaseName. See also Building the Connection URL.
With recent JDBC drivers, it is not necessary to explicitly load the driver class in simple Java applications, so instead of step 1, you could also remove the Class.forName line.
Also make sure you are using a recent version of the driver, see the mssql-jdbc project on GitHub (latest stable version at time of writing is 7.0.0).

Correct the driver class name:
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");

ORMLite exception : java.sql.SQLException: ResultSet already requested

In one of our Java app we have a SQLite DB and multiple threads read and write to the same DB (different tables). These multiple threads however use the same database connection object (ORMLite's DaoManager.createDao()).
We are getting this SQLException (Resultset already requested) randomly whenever some insert/update statement is executing. Below is the stack trace of one such instance.
java.sql.SQLException: Unable to run insert stmt on object ABCD-164: INSERT INTO `pos_order` (`bill_number` ,`order_status` ,`order_type` ,`payment_mode` ,`reference_bill_number` ,`table_selected` ,`sub_total` ,`discountable_sub_total` ,`total` ,`total_discount` ,`discount_type` ,`discount_value` ,`total_tax` ,`service_charge` ,`service_tax` ,`vat` ,`delivery_charge` ,`packaging_charge` ,`amount_paid` ,`waiter` ,`delivery_boy` ,`order_source` ,`delivery_source` ,`card_type` ,`card_name` ,`client_creation_time` ,`client_updation_time` ,`order_comment` ,`customer_feedback` ,`is_deleted` ,`payment_status` ,`pos_outlet_id` ,`is_sync` ,`delivery_status` ,`shipment_id` ,`response_code` ,`delivery_time` ,`custom_packaging_charge_enable` ,`custom_delivery_charge_enable` ,`receipt_printed` ,`total_person` ,`order_origin` ,`json` ,`oo_system_id` ,`pre_order` ,`pre_order_time` ) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)
at com.j256.ormlite.misc.SqlExceptionUtil.create(SqlExceptionUtil.java:22)
at com.j256.ormlite.stmt.mapped.MappedCreate.insert(MappedCreate.java:135)
at com.j256.ormlite.stmt.StatementExecutor.create(StatementExecutor.java:450)
at com.j256.ormlite.dao.BaseDaoImpl.create(BaseDaoImpl.java:310)
at com.j256.ormlite.dao.BaseDaoImpl.createOrUpdate(BaseDaoImpl.java:336)
at com.limetray.pos.dbmanagers.implementations.PosOrderDaoImpl.insert(PosOrderDaoImpl.java:50)
at com.limetray.pos.controllers.BillingSectionController.lambda$10(BillingSectionController.java:808)
at com.limetray.pos.utilities.SingleTaskExecutor$1.call(SingleTaskExecutor.java:37)
at javafx.concurrent.Task$TaskCallable.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.sql.SQLException: ResultSet already requested
at org.sqlite.jdbc3.JDBC3Statement.getResultSet(JDBC3Statement.java:136)
at org.sqlite.jdbc3.JDBC3PreparedStatement.executeQuery(JDBC3PreparedStatement.java:69)
at org.sqlite.jdbc3.JDBC3DatabaseMetaData.getGeneratedKeys(JDBC3DatabaseMetaData.java:1796)
at org.sqlite.jdbc3.JDBC3Statement.getGeneratedKeys(JDBC3Statement.java:346)
at com.j256.ormlite.jdbc.JdbcDatabaseConnection.insert(JdbcDatabaseConnection.java:173)
at com.j256.ormlite.stmt.mapped.MappedCreate.insert(MappedCreate.java:91)
... 13 more
Any help would be much appreciated. Thanks.

In one of our Java app we have a SQLite DB and multiple threads read and write to the same DB (different tables).
With the SQLite database, you can only have one connection to it at a time. The database has internal locking that ensures that no two threads are using the same connection at the same time but that doesn't stop the DAOs from allowing multiple threads to cause problems like you are having.
Caused by: java.sql.SQLException: ResultSet already requested
In your case, because multiple threads are using the same connection, this exception is getting thrown when one thread asks for results on a connection that has already been asked my another thread. Their queries are improperly being interleaved.
It's important to realize that this has nothing to do with the underlying database. Sqlite has its own locking that blocks concurrent access by multiple threads. But in this case, we are having problems with multiple threads using the same connection.
Right now ORMLite does not have a ConnectionSource that provides a synchronized single connection to the underlying database so you will have to do your own external locking. You could extend the JdbcSingleConnectionSource class and use a ReentrantLock to enforce the controls. Maybe something like:
public class LockedJdbcSingleConnectionSource extends JdbcSingleConnectionSource {
private final ReentrantLock lock = new ReentrantLock();
// called from JdbcSingleConnectionSource.getReadOnlyConnection() ...
public DatabaseConnection getReadWriteConnection() {
lock.lock();
return super.getReadWriteConnection();
}
public void releaseConnection(DatabaseConnection connection) {
super.releaseConnection(connection);
lock.unlock();
}
}

Oracle JDBC DriverManager.getConnection() hangs

We have several servers that each run an Oracle database 11g Release 11.2.0.1.0 - 64bit. We are connecting via JDBC like this:
public Connection createConnection(String drvClass, String connURL, String user, String pass)
throws ClassNotFoundException, SQLException {
Class.forName(drvClass);
Connection conn = DriverManager.getConnection(connURL, user, pass);
for (SQLWarning warn = conn.getWarnings(); warn != null; warn = warn.getNextWarning()) {
System.out.println("SQL Warning:");
System.out.println("State : " + warn.getSQLState());
System.out.println("Message: " + warn.getMessage());
System.out.println("Error : " + warn.getErrorCode());
}
return conn;
}
drvClass would be oracle.jdbc.OracleDriver. The program which tries to connect runs on each server. The database is reachable from out of other programs with the exact same connection properties.
It is also possible to let this program run on another server and let it connect to the problematic database. It can establish the connection.
The program does not work if it's running on the server locally. We tried both IP and servername.
On one server the code hangs at DriverManager.getConnection() an I cannot find out why. Does anyone have any idea what could cause this?
There is no entry about this in the DB logs.
Stacktrace of blocking thread:
"pool-27-thread-1" - Thread t#1483
java.lang.Thread.State: RUNNABLE
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at oracle.net.ns.Packet.receive(Packet.java:239)
at oracle.net.ns.NSProtocol.connect(NSProtocol.java:255)
at oracle.jdbc.driver.T4CConnection.connect(T4CConnection.java:973)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:291)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:490)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:202)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:33)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:474)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.companyname.DBConnectionInternal.DBConnection.createConnection(DBConnection.java:19)
at com.companyname.exportadapter.ExportCollector.initDatabase(ExportCollector.java:259)
at com.companyname.exportadapter.ExportCollector.run(ExportCollector.java:120)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Locked ownable synchronizers:
- locked <50be77> (a java.util.concurrent.ThreadPoolExecutor$Worker)
If i set DriverManager.setLoginTimeout(10)
then i get
Io exception: Socket read timed out.

you may making some unneccessary connections.
make Connection class static
,whenever you are creating new connection check older is alive or close then and then you must create new connection other wise return old connection.
like
if(conn!=null & !conn.isClosed()){
// code for create connection
}
It also depends on how the database side is configured, so check it with DBA of your system.
I would like to suggest using Connection pooling.
hope this helps.

You might want to enable JDBC debug logging for the ojdbc driver: http://docs.oracle.com/cd/B28359_01/java.111/b31224/diagnose.htm
That might give you some information about what the driver is doing.
Have you tried telnet-ing to the database server from the client machine (to assert it's reachable)?

The server was misconfigured. For some reason it had a virtual adapter configured which returned an ip to which nothing could connect. From outside the resolving worked correctly. Don't know why it never timed out with the wrong IP though.

Lotus Notes Agent - Java Security Error

I have a Lotus Notes Agent written in Java which should pop up a message to the user after it is executed by clicking a button in the Notes client. Trying to display the pop-up causes an error which I see in the Java Debug console as :
java.security.AccessControlException: Access denied (java.lang.RuntimePermission exitVM.0)
at java.security.AccessController.checkPermission(AccessController.java:108)
at java.lang.SecurityManager.checkPermission(SecurityManager.java:544)
at COM.ibm.JEmpower.applet.AppletSecurity.superDotCheckPermission(AppletSecurity.java:1449)
at COM.ibm.JEmpower.applet.AppletSecurity.checkRuntimePermission(AppletSecurity.java:1311)
at COM.ibm.JEmpower.applet.AppletSecurity.checkPermission(AppletSecurity.java:1611)
at COM.ibm.JEmpower.applet.AppletSecurity.checkPermission(AppletSecurity.java:1464)
at java.lang.SecurityManager.checkExit(SecurityManager.java:756)
at java.lang.Runtime.exit(Runtime.java:99)
at java.lang.System.exit(System.java:279)
at ClipboardTest.main(Unknown Source)
at JavaAgent.NotesMain(Unknown Source)
at lotus.domino.AgentBase.runNotes(Unknown Source)
at lotus.domino.NotesThread.run(Unknown Source)
My agent code is
import lotus.domino.*;
import javax.swing.JOptionPane;
public class JavaAgent extends AgentBase {
public void NotesMain() {
try {
Session session = getSession();
AgentContext agentContext = session.getAgentContext();
// (Your code goes here)
Document cdoc = agentContext.getDocumentContext();
String[] notesURL = new String[] {cdoc.getNotesURL()};
ClipboardTest.main(notesURL);
JOptionPane.showMessageDialog(null,"message","title",JOptionPane.WARNING_MESSAGE);
} catch(Exception e) {
e.printStackTrace();
}
}
}
I have manager access to the Database. What could be causing this error?

First look at what the error actually is:
Access denied (java.lang.RuntimePermission exitVM.0)
You are telling the VM to die and you do not have the rights to do this. If you had, you would cause anything else running on that JVM instance to die as well, possibly leading to a hang/crash.
Secondly your code is failing in the ClipboardTest.main() method, which you haven't posted any code for.
In the agent properties there is an option to add debug data. This will give you the exact line number that is causing the issue.
My guess is you have a System.exit() call in the ClipboardTest.main() . It shouldn't be there.

Set Oracle 10g database connection timeout in Java

I tried to set a connection timeout with the following code:
public class ConnectionTimeout {
public static void main(String[] args) throws Exception {
String entry = "jdbc:oracle:thin:#xxx:1521:xxx";
Connection con=null;
Class.forName("oracle.jdbc.driver.OracleDriver");
DriverManager.setLoginTimeout(1);
con=DriverManager.getConnection(entry,"username","password");
Statement s=con.createStatement();
s.execute("select 1 from dual");
s.close();
con.close();
}
}
The instance xxx is not existing. But I get the following exception:
Exception in thread "main" java.sql.SQLException: E/A-Exception: Socket is not connected
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:146)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:255)
at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:387)
at oracle.jdbc.driver.PhysicalConnection.<init>(PhysicalConnection.java:439)
at oracle.jdbc.driver.T4CConnection.<init>(T4CConnection.java:165)
at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:35)
at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:801)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at my.package.connection.timeout.ConnectionTimeout.main(ConnectionTimeout.java:22)
How I can implement a timeout to an not existing or available Oracle database instance?
Edit:
If I set the DriverManager.setLoginTimeout(30); to 30 second, the exception happens so fast as before!

Your DriverManager.setLoginTimeout(1); sets the maximum time in seconds for the driver to wait while connecting to the database. In your case, it's set to 1.
To have no limit, set setLoginTimeout(0) where 0 means no limit.
I hope this helps.
Update if your instance xxx doesn't exists, how would you expect your Oracle Driver to connect to the database? It won't make any difference how long you set your loginTimeout there's not "host" to connect to.

Because, in Java doc, it shows: timeout in seconds, but in the implementation of JDBC Oracle, it is milliseconds.
You can try using a measure of milliseconds.