Tired of maintenance

July 2, 2010, 11:59 AM

I have migrated this blog to http://foxbrush.wordpress.com/

Unable to spend much more time on maintenance :(

Category: Announcement  |  Comments Off

Opening a URL connection in your mobile phone

June 15, 2010, 9:35 AM

Streams can be opened in several ways

1. HTTP communication:

Connection hc = Connector.open("http://www.wirelessdevnet.com");

2. Stream-based Socket communication:

Connection sc = Connector.open("socket://localhost:9000");

3. Datagram-based socket communication:

Connection dc = Connector.open("datagram://:9000");

4. Serial port communication:

Connection cc = Connector.open("comm:0;baudrate=9000");

5. File I/O

Connection fc = Connector.open("file://foo.dat");

I have used the HTTP communication.

HttpConnection c = (HttpConnection) Connector.open(url.getString());
this.responseCode = c.getResponseCode();
c.close();

While running, I got a warning in the log says…

Warning: To avoid potential deadlock, operations that may block, such as networking,
should be performed in a different thread than the commandAction() handler.

In addition, the phone emulator is not responding for the alert :( 

mobiletest Midlet Suite wants to connect to http:///...... using airtime. This may result in charges.
Is it OK to use airtime?

No response for this alert when I press yes or no several times!

http://forums.sun.com/thread.jspa?threadID=5339547

We need to write the HTTP connection in a separate thread, so that the main thread wont get blocked with it.

———
Ref. http://www.wirelessdevnet.com/channels/java/features/j2me_http.phtml

Tags: ,
Category: J2ME  |  Comments Off

a different object with the same identifier value was already associated with the session

May 14, 2010, 8:48 PM

This is purely a Hibernate problem. I have one to many relationship between tables. Mapping table c contains the relations between table a and table b. When I try to save a new object in a, which has a set of b objects (All those b objects are already existing), I got an Hibernate exception saying

a different object with the same identifier value was already  associated with the session:
[org.grassfield.common.entity.User#4];  nested exception is org.hibernate.NonUniqueObjectException:
a different  object with the same identifier value was already associated with the  session:
[org.grassfield.common.entity.User#4]

Seems to be quiet common issue for one to many or many to many relationship in hibernate. Need to look at it tomorrow.

Finally I found the table I have created to store the many to many relation is goofy. I removed the id column (autoincrement and PK). It resolved the issue. finally I have only two columns to store the relations.

Done!

Category: Errors, hibernate  |  Comments Off

Expression eKey is undefined on line 71, column 63 in template/simple/fielderror.ftl

May 12, 2010, 3:40 PM

This is one nasty exception occured due to carelessness.  I have added one field error in my action.

super.addFieldError("userName", "User name is null");

Instead of the field name “userName”, I have given the variable itself :) 

super.addFieldError(userName, "User name is null");

Replacing this removed this error.

10:40:24,859        ERROR runtime:96 -
Expression eKey is undefined on line 71, column 63 in template/simple/fielderror.ftl.
The problematic instruction:
----------
==> assignment: eValue=fieldErrors[eKey] [on line 71, column 33 in template/simple/fielderror.ftl]
----------
Java backtrace for programmers:
----------
freemarker.core.InvalidReferenceException: Expression eKey is undefined on line 71, column 63 in template/simple/fielderror.ftl.
 at freemarker.core.TemplateObject.assertNonNull(TemplateObject.java:124)
 at freemarker.core.DynamicKeyName._getAsTemplateModel(DynamicKeyName.java:85)
 at freemarker.core.Expression.getAsTemplateModel(Expression.java:89)
 at freemarker.core.Assignment.accept(Assignment.java:90)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.MixedContent.accept(MixedContent.java:92)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.IteratorBlock$Context.runLoop(IteratorBlock.java:167)
 at freemarker.core.Environment.visit(Environment.java:415)
 at freemarker.core.IteratorBlock.accept(IteratorBlock.java:102)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.MixedContent.accept(MixedContent.java:92)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.ConditionalBlock.accept(ConditionalBlock.java:79)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.IfBlock.accept(IfBlock.java:82)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.MixedContent.accept(MixedContent.java:92)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.ConditionalBlock.accept(ConditionalBlock.java:79)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.MixedContent.accept(MixedContent.java:92)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.Environment.process(Environment.java:188)
 at freemarker.template.Template.process(Template.java:237)
 at org.apache.struts2.components.template.FreemarkerTemplateEngine.renderTemplate(FreemarkerTemplateEngine.java:182)
 at org.apache.struts2.components.UIBean.mergeTemplate(UIBean.java:559)
 at org.apache.struts2.components.UIBean.end(UIBean.java:513)
 at org.apache.struts2.views.jsp.ComponentTagSupport.doEndTag(ComponentTagSupport.java:42)
 at org.apache.jsp.index_jsp._jspx_meth_s_005ffielderror_005f0(index_jsp.java:193)
 at org.apache.jsp.index_jsp._jspx_meth_s_005fform_005f0(index_jsp.java:132)
 at org.apache.jsp.index_jsp._jspService(index_jsp.java:78)
 at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
 at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
 at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
 at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)
 at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436)
 at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374)
 at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)
 at org.apache.struts2.dispatcher.ServletDispatcherResult.doExecute(ServletDispatcherResult.java:154)
 at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:186)
 at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:361)
 at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:265)
 at com.eginnovations.common.interceptor.AuthorizationInterceptor.intercept(AuthorizationInterceptor.java:42)
 at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
 at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
 at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:468)
 at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
 at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:76)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
 at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
 at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
 at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
 at java.lang.Thread.run(Unknown Source)
May 12, 2010 10:40:24 AM org.apache.catalina.core.ApplicationDispatcher invoke
SEVERE: Servlet.service() for servlet jsp threw exception
Expression eKey is undefined on line 71, column 63 in template/simple/fielderror.ftl.
The problematic instruction:
----------
==> assignment: eValue=fieldErrors[eKey] [on line 71, column 33 in template/simple/fielderror.ftl]
----------
Java backtrace for programmers:
----------
freemarker.core.InvalidReferenceException: Expression eKey is undefined on line 71, column 63 in template/simple/fielderror.ftl.
 at freemarker.core.TemplateObject.assertNonNull(TemplateObject.java:124)
 at freemarker.core.DynamicKeyName._getAsTemplateModel(DynamicKeyName.java:85)
 at freemarker.core.Expression.getAsTemplateModel(Expression.java:89)
 at freemarker.core.Assignment.accept(Assignment.java:90)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.MixedContent.accept(MixedContent.java:92)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.IteratorBlock$Context.runLoop(IteratorBlock.java:167)
 at freemarker.core.Environment.visit(Environment.java:415)
 at freemarker.core.IteratorBlock.accept(IteratorBlock.java:102)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.MixedContent.accept(MixedContent.java:92)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.ConditionalBlock.accept(ConditionalBlock.java:79)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.IfBlock.accept(IfBlock.java:82)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.MixedContent.accept(MixedContent.java:92)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.ConditionalBlock.accept(ConditionalBlock.java:79)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.MixedContent.accept(MixedContent.java:92)
 at freemarker.core.Environment.visit(Environment.java:208)
 at freemarker.core.Environment.process(Environment.java:188)
 at freemarker.template.Template.process(Template.java:237)
 at org.apache.struts2.components.template.FreemarkerTemplateEngine.renderTemplate(FreemarkerTemplateEngine.java:182)
 at org.apache.struts2.components.UIBean.mergeTemplate(UIBean.java:559)
 at org.apache.struts2.components.UIBean.end(UIBean.java:513)
 at org.apache.struts2.views.jsp.ComponentTagSupport.doEndTag(ComponentTagSupport.java:42)
 at org.apache.jsp.index_jsp._jspx_meth_s_005ffielderror_005f0(index_jsp.java:193)
 at org.apache.jsp.index_jsp._jspx_meth_s_005fform_005f0(index_jsp.java:132)
 at org.apache.jsp.index_jsp._jspService(index_jsp.java:78)
 at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
 at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
 at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
 at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)
 at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436)
 at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374)
 at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)
 at org.apache.struts2.dispatcher.ServletDispatcherResult.doExecute(ServletDispatcherResult.java:154)
 at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:186)
 at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:361)
 at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:265)
 at com.eginnovations.common.interceptor.AuthorizationInterceptor.intercept(AuthorizationInterceptor.java:42)
 at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
 at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
 at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:468)
 at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
 at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:76)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
 at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
 at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
 at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
 at java.lang.Thread.run(Unknown Source)
Tags:
Category: Errors, struts  |  Comments Off

JDBCExceptionReporter:77 – SQL Error: 0, SQLState: 08S01

May 11, 2010, 1:12 PM

I have a scheduled job running with spring beans. It is scheduled such that it will run once in a day. Whenever I restart the webapp, it is running for the first day. but on the second day onwards, it is not running – quits with the below exception :( Seems to be an issue with DB connectivity. Need to look at it.

00:54:28,090  WARN JDBCExceptionReporter:77 - SQL Error: 0, SQLState: 08S01
00:54:28,090 ERROR JDBCExceptionReporter:78 - Communications link failure due to underlying exception: 

** BEGIN NESTED EXCEPTION ** 

java.net.SocketException
MESSAGE: Software caused connection abort: socket write error

STACKTRACE:

java.net.SocketException: Software caused connection abort: socket write error
 at java.net.SocketOutputStream.socketWrite0(Native Method)
 at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
 at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
 at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
 at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
 at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2744)
 at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1612)
 at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
 at com.mysql.jdbc.Connection.execSQL(Connection.java:3283)
 at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1332)
 at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1467)
 at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:93)
 at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:186)
 at org.hibernate.loader.Loader.getResultSet(Loader.java:1787)
 at org.hibernate.loader.Loader.doQuery(Loader.java:674)
 at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
 at org.hibernate.loader.Loader.doList(Loader.java:2220)
 at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2104)
 at org.hibernate.loader.Loader.list(Loader.java:2099)
 at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:94)
 at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1569)
 at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:283)
 at com.eginnovations.license.dao.LicenseDAO.listExpiry(LicenseDAO.java:106)
 at com.eginnovations.license.service.LicenseService.listExpiry(LicenseService.java:291)
 at com.eginnovations.license.jobs.ExpiryTimer.run(ExpiryTimer.java:85)
 at java.util.TimerThread.mainLoop(Timer.java:512)
 at java.util.TimerThread.run(Timer.java:462)

** END NESTED EXCEPTION **

Last packet sent to the server was 15 ms ago.
00:54:28,090 ERROR ExpiryTimer:95 - Error in expiry job
org.hibernate.exception.JDBCConnectionException: could not execute query
 at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:74)
 at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
 at org.hibernate.loader.Loader.doList(Loader.java:2223)
 at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2104)
 at org.hibernate.loader.Loader.list(Loader.java:2099)
 at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:94)
 at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1569)
 at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:283)
 at com.eginnovations.license.dao.LicenseDAO.listExpiry(LicenseDAO.java:106)
 at com.eginnovations.license.service.LicenseService.listExpiry(LicenseService.java:291)
 at com.eginnovations.license.jobs.ExpiryTimer.run(ExpiryTimer.java:85)
 at java.util.TimerThread.mainLoop(Timer.java:512)
 at java.util.TimerThread.run(Timer.java:462)
Caused by: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: 

** BEGIN NESTED EXCEPTION ** 

java.net.SocketException
MESSAGE: Software caused connection abort: socket write error

STACKTRACE:

java.net.SocketException: Software caused connection abort: socket write error
 at java.net.SocketOutputStream.socketWrite0(Native Method)
 at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
 at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
 at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:65)
 at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:123)
 at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2744)
 at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1612)
 at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
 at com.mysql.jdbc.Connection.execSQL(Connection.java:3283)
 at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1332)
 at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1467)
 at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:93)
 at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:186)
 at org.hibernate.loader.Loader.getResultSet(Loader.java:1787)
 at org.hibernate.loader.Loader.doQuery(Loader.java:674)
 at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
 at org.hibernate.loader.Loader.doList(Loader.java:2220)
 at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2104)
 at org.hibernate.loader.Loader.list(Loader.java:2099)
 at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:94)
 at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1569)
 at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:283)
 at com.eginnovations.license.dao.LicenseDAO.listExpiry(LicenseDAO.java:106)
 at com.eginnovations.license.service.LicenseService.listExpiry(LicenseService.java:291)
 at com.eginnovations.license.jobs.ExpiryTimer.run(ExpiryTimer.java:85)
 at java.util.TimerThread.mainLoop(Timer.java:512)
 at java.util.TimerThread.run(Timer.java:462)

** END NESTED EXCEPTION **

Last packet sent to the server was 15 ms ago.
 at com.mysql.jdbc.MysqlIO.send(MysqlIO.java:2759)
 at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1612)
 at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
 at com.mysql.jdbc.Connection.execSQL(Connection.java:3283)
 at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1332)
 at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1467)
 at org.apache.commons.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:93)
 at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:186)
 at org.hibernate.loader.Loader.getResultSet(Loader.java:1787)
 at org.hibernate.loader.Loader.doQuery(Loader.java:674)
 at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
 at org.hibernate.loader.Loader.doList(Loader.java:2220)
 ... 10 more
Tags: , ,
Category: Errors, Spring, hibernate  |  Comments Off
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