Suneel Gundlapalli's blog

glassfish EMBEDDED Broker start failure:code = 1

suneel — Tue, 06 Dec 2011 17:36:42 +0000

You might get this error when you copy the glassfish directory to a different machine, or the existing machine gets a new IP address. The fix is to delete the file under \imq\instances\imqbroker\lock . More on this here:http://old.nabble.com/Glassfish-V2-failed-to-start,-broker%3Dembedded,-failure%3Acode-%3D-1-td17728741.html

ubuntu 11.04 “cannot display this video mode” error

suneel — Tue, 11 Oct 2011 19:24:46 +0000

I started getting this with my onboard Nvidia graphics adapter. I would get this message during bootup and during shutdown/restart. It went away after installing the “recommended/current version” Nvidia driver instead of the generic driver. Do not install version 173 as it had the same issue.

The current version fixed the problem but introduced another issue. Now all I see is just white screen on applications like Eclipse etc.

Then I tried uninstalling all the Nvidia drivers. Now I get the old UI instead of Unity. So I reinstalled version 173 and everything works fine now!!!!!!!!!!!

removing timezone from webservice dates (XMLGregorianCalendar) for date of birth etc.

suneel — Tue, 09 Aug 2011 20:51:51 +0000

If you have webservice that recieves a XMLGregorianCalendar as a parameter, if you try to obtain date from it, you might see a difference of 1 day due to timezone differences. (i.e., xmlDate.toGregorianCalendar().getTime()) . The solution is to eliminate the timeZone from xmldate using the following:

xmlDt.setTimezone( DatatypeConstants.FIELD_UNDEFINED )

More details on this here:

http://knowhow.amazers.net/space/dev/java+tips/Hacks+around+XMLGregorianCalendar

Compling JSP using org.apache.jasper.JspC generated empty web.xml when run in eclipse 64bit

suneel — Fri, 29 Jul 2011 20:27:23 +0000

I was getting an empty web.xml when I tried to compile the JSPs using JspC shown above. I was running this using ant script and this ant script was run using eclipse. Turns out, eclipse was using a 64bit JDK but the ant script had a 32bit JDKs tools.jar in classpath. Making that point to the 64bit jdk in the script solved the issue.

oracle sqldeveloper column ordering and hiding

suneel — Wed, 13 Jul 2011 20:34:53 +0000

You can right click on any column in data view or query result and reorder the columns. This is useful when you have a table with large number of columns and you are only interested in few columns like status etc. Sometimes you may not see this option when you right click. This is a bug I noticed in 3.0.0.04. In such cases, just restart sqldeveloper.

Debugging “Hibernate bind parameters not getting logged”

suneel — Mon, 27 Jun 2011 17:47:52 +0000

I did set org.hibernate.type=trace. But it still didn’t print bind parameters. So decided to debug through the hibernate source code. The code for logging the bind parameters exists in org.hibernate.type.NullableType.nullSafeSet(PreparedStatement, Object, int). Found that it is infact logging the bind parameters. But I still don’t see those in the log file or the console. I might have to dig deeper into the org.slf4j.Logger.trace method.

The issue turned out to be with the appender and the appender threshold. We have 3 appenders in our log4j configuration and we were using only one of the the 3 for the category “org.hibernate.type”. And this appender had threshold set WARN, as a result it kept supressing all the “trace” logs. Another thing you need to be careful about this is that you need to initialize log4j before calling hibernate API. This is because hibernate determines the log level at class load time using the following statement:
private static final boolean IS_VALUE_TRACING_ENABLED = LoggerFactory.getLogger( StringHelper.qualifier( Type.class.getName() ) ).isTraceEnabled();

Marking cookie as HTTPOnly in J2EE 5

suneel — Thu, 19 May 2011 20:54:19 +0000

The Cookie API in J2EE 2.5 doesn’t have a ‘setHttpOnly’ method. So I had to resort to a work around to achieve this. Instead of doing a response.addCookie, I had to write a custom method that writes the “Set-Cookie” header and use StringBuilder to construct the header value.

Connecting a Windows 7 machine to Windows 2000 server domain controller

suneel — Sun, 24 Apr 2011 07:33:46 +0000

You cannot connect unless the Windows 2000 machine has service pack 4. So install that from Microsoft. Then make the NTLM changes suggested here:

http://ykyuen.wordpress.com/2009/09/04/windows-7-cannot-connect-to-newtork-drive/

You might then get the DNS error. The fix is here (changing the DNS server on Win 7 point to Server ip):

http://answers.microsoft.com/en-us/windows/forum/windows_7-networking/cannot-add-windows-7-pc-to-domain-get-the/f6b8bc13-18b6-4a67-afa5-755d98a51776

Hiberate and JDBC in same transaction – Flush is a must if JDBC code depends on changes made by Hibernate

suneel — Fri, 01 Apr 2011 17:36:35 +0000

Hibernate may not issue queries or inserts to the database until the transaction is closed. So any change made to DB using Hibernate is only visble to Hibernate API. So if you have a JDBC code that executes after some Hibernate modifications, that JDBC code won’t see the change (like if JDBC code is accessing the same record hibernate modified, as in a legacy code) unless you issue a flush in Hibernate.

OutOfMemory – GC OverHead exceeded – Not closing prepared statements – JDBC with Oracle 11g

suneel — Fri, 01 Apr 2011 17:13:05 +0000

I wrote a unit test using Spring and for datasource, I used org.springframework.jdbc.datasource.SingleConnectionDataSource. This unit test was calling a legacy code in loop for 5000 times. After 3000 iterations, it was throwing a OutOfMemory (OOM) error. After further research, it turned out to be an issue with legacy code that this unit test was calling that didn’t close prepared statements. And since this is a ‘single connection’ datasource, I never got the ‘connections exhausted’ error. Looks like when ever you call a connection.prepareStatement, the connection object created a few objects and stored them in. As a result, the connection object grew in size and eventually we got the OOM error. Closing the prepared statement fixed the issue.

Before this incident, I didn’t think we could have memory leaks if a statement is not closed.