Thread: jdbc connections

I had existing function (f1) that opens and does select sql and returns results and closes connection.

Now I need to call the f1 many time. so in a loop

loop begins
f1
loop ends.

As long as the f1 opens and closes the jdbc connection I should not have any problem whatever the number of times it loops.

But I do see problem max connections sql exception

java.sql.SQLException: Network error IOException: No buffer space available (maximum connections reached?): connect
at net.sourceforge.jtds.jdbc.ConnectionJDBC2.<init>(C onnectionJDBC2.java:385)
at net.sourceforge.jtds.jdbc.ConnectionJDBC3.<init>(C onnectionJDBC3.java:50)
at net.sourceforge.jtds.jdbc.Driver.connect(Driver.ja va:182)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.cleverdevices.bustime.util.DatabaseUtil.openDa tabaseConnection(DatabaseUtil.java:68)
at com.cleverdevices.bustime.scheduleevaluator.Schedu leEvaluator.getHistoricalScheduleAdherenceResults( ScheduleEvaluator.java:877)
at com.cleverdevices.bustime.scheduleevaluator.Schedu leEvaluatorIFImpl.getHistoricalScheduleAdherenceRe sults(ScheduleEvaluatorIFImpl.java:450)
at sun.reflect.GeneratedMethodAccessor3.invoke(Unknow n Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Un known Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.rmi.server.UnicastServerRef.dispatch(Unknown Source)
at sun.rmi.transport.Transport$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Unknown Source)
at sun.rmi.transport.tcp.TCPTransport.handleMessages( Unknown Source)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandl er.run0(Unknown Source)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandl er.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run Task(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run (Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.net.SocketException: No buffer space available (maximum connections reached?): 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.GeneratedMethodAccessor4.invoke(Unknow n Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Un known Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.sourceforge.jtds.jdbc.SharedSocket.createSocke tForJDBC3(SharedSocket.java:304)
at net.sourceforge.jtds.jdbc.SharedSocket.<init>(Shar edSocket.java:255)
at net.sourceforge.jtds.jdbc.ConnectionJDBC2.<init>(C onnectionJDBC2.java:310)
... 20 more


obviously if I connection before loop and close after loop it is ok. But my theory as long as we close everytime it should work ..

what is missing. "netstat" lists the db connections ports..

ofcourse when I stop the tomcat server..it clears.

my question in not regarding my code.

My questions is if we loop open/close connection lets say 20k to 30k times, will that be a problem? I thought as long as we open and close, it should not be a problem. or is there a limitation?

thanks. In my try, it did not work and i got max connections reached exception. I moved the open/close outside the loop. I also thought theoratically it should work. but looks like the loop goes faster that the open/close.