user3600935 user3600935 - 1 day ago 4
Java Question

Java connection pooling (JNDI) not work affter half a aday

I have a web app which uses JNDI for connection polling (DB server is MySql),

There is many request to web application and it has a web service used by one other web application.

It work fine but after a while in not works and after some no-processed commands in web service, the error below appears:


java.sql.SQLException: Cannot get a connection, general error
javax.naming.NameNotFoundException: Name [java:/comp/env] is not bound in this Context. Unable to find [java:].


I copy app aout put in below.

please notice i force app to print "+++++=====>>>> number of connection X"

when for new connection ( if it was new connection X increased)

and after closing connection "------=====>>>> number of connection X"

note 2 : Whenever web service is called a "%%%%>>>>> web Service request for" string will be printed in the out put and then a "SELECT" command will run and print in the out put,but when system crashed the request to the web service received, but not proceed.

So look up for "+++++=====>>>>" and "+++++=====>>>>" and pay attention in defrence between "%%%%>>>>> web Service request for" in the beginning and at the end.

The out put is like below :

java out put file

public void close() throws SQLException {
connection.close();
counter--;
ServerLog.Print("------=====>>>> number of connection " + counter);
ServerLog.Print("Database connection is closed ...");
}


This are some methods in below:

public jjDatabaseWeb() throws SQLException, NamingException {
ctx = new InitialContext();
Context initCtx = (Context) ctx.lookup("java:/comp/env");
DataSource ds = (DataSource) initCtx.lookup("jdbc/MyDB");
connection = ds.getConnection();
counter++;
ServerLog.Print("+++++=====>>>> number of connection " + counter);
}


And in below is web service method that which calls whit other services in LAN :

/**
* this Method returns a string result; if(result =="" OR result==null){ do
* your work }else{ show user result as message (result is HTML ) }
*
* @param stdNubmer
* @param nationalId Is not important
* @return String result (as HTML )
* @throws javax.naming.NamingException
*/
@WebMethod(operationName = "studentCheck")
public String studentCheck(@WebParam(name = "stdNubmer") String stdNubmer, @WebParam(name = "nationalId") String nationalId) {

try {
ServerLog.Print("%%%%>>>>> web Service request for :" + stdNubmer);
try {
jjDatabaseWeb db = new jjDatabaseWeb();
DefaultTableModel dtm = db.Select(StdInfo.tableName, StdInfo._step + "," + StdInfo._alerts + "," + StdInfo._lastAertDate + "," + StdInfo._name + "," + StdInfo._family, StdInfo._stdNumber + "=" + stdNubmer);
List<Map<String, Object>> row = jjDatabaseWeb.separateRow(dtm);
db.close();//
if (row.size() == 1) {
if (!row.get(0).get(StdInfo._step).toString().equalsIgnoreCase("5")) {
int date = new jjCalendar_IR().getDBFormat_8length();
int lastAlertDate = Integer.parseInt(row.get(0).get(StdInfo._lastAertDate).toString());
int alerts = Integer.parseInt(row.get(0).get(StdInfo._alerts).toString());
if ((date - 5) <= lastAlertDate) {
return "";
}
StringBuilder html = new StringBuilder("");
html.append("<HTML>...</HTML>");
return html.toString();
}
}
return "";
} catch (NamingException ex) {
Logger.getLogger(csaWebService.class.getName()).log(Level.SEVERE, null, ex);
}
} catch (SQLException ex) {
Logger.getLogger(csaWebService.class.getName()).log(Level.SEVERE, null, ex);
ServerLog.Print(ex);
Server.ErrorHandler(ex);
return "";
}
return "";
}


}

Answer

There was so many connections that witch opened and not closed .

Be careful about close() for connections.

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