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ernest fakudze

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Recent posts by ernest fakudze

Hello to all,

I consider myself an intermediate Java developer and I still have a great deal to learn before I become a pro. I understand the Java language API and I can use it. I also know how to develop a Java web app using JSP/Servlets, JSTL, DisplayTag etc. Recently I've been learning Spring and Hibernate. I can now persist some Pojos into MySQL and read them back. My application uses Spring MVC and Spring Security to protect some backend modules. The most challenging Java project I've been involved in so far was a RMI application. Here is how it worked: we had a J2EE app running on Solaris and it needed to convert PowerPoint presentations into PNG images. We would then feed the images into the J2EE app in order to synchronize video with PowerPoint. The Java application which converted the PowerPoint slides into images ran on a Windows machine. I enjoyed that task and I used RMIIO to stream the data between the two JVMs.

I'm comfortable working with Tomcat and recently my main task at work was deploying J2EE apps into Jetty. I also had to deal with memory issues and ensure that the applications were running smoothly. I use Eclipse IDE for development and I'm familiar with checking in/out stuff from CVS. Ant is my favourite build tool because it gives me so much flexibility when it comes to managing my project. I'm very comfortable in a Linux environment.

What I'm looking for:

I want to join a team of Java developers who can help me grow as a developer. I'm not senior nor junior and I know that I need to work hard to get to senior level. I'm passionate about programming and I'm always keen to learn new technologies. In the past I've played around with Struts and JSF. My problem is that I find it difficult to get a company that needs people of my level. Many companies are advertising jobs for seasoned Spring/Hibernate developers. Does anyone know any company that would be interested in recruiting someone like me? I just need the chance and once I've got it I can prove myself. I'm a very friendly person and I enjoy meeting people from different backgrounds. People that know me say I'm always smiling. I'm originally from Swaziland but I've lived in London for the past 15 years. I'm now a British citizen. I'm 33 next June. I play basketball and do cycling when the English weather is good.

Thanks for reading this and I hope someone might have some suggestions. I'm available for work on March 1st and I can be contacted on the email address: ernie_at_ernieboy_dot_com.

Kind regards,
Ernest

11 years ago
Thanks Kees, I will experiment with the heap minimum and maximum sizes. They are currently not set.
11 years ago
Greetings to all,

In my environment (Solaris) I host applications for several clients and each application runs on each own Jetty server instance. I'm doing this to isolate each customer such that when one Jetty goes down only one customer is affected. The problem I have is that these Jetty servers are eating up a great deal of swap memory, some of them up to 410MB. I need to reduce this memory footprint but I'm not sure how to do it. My apps are Spring/Hibernate based. Each application has jars in WEB-INF/lib totaling 32MB. Any suggestions?

Thanks in advance.
11 years ago
Hello to all,

I have a Jetty server running a simple J2EE application on port 8085. In Apache I have a RewriteRule which simply proxies to the Jetty server when given a certain URL pattern. See an
example below of my Apache virtual host:



The RewriteRule seems to be working ok and it takes the user to the Jetty app. The Jetty app has a logon admin screen. Most of the time, when the user has logged onto the admin screen
and tries to perform an action, the app redirects the user to the logon screenagain. When the user logs in again the app then redirects them to the originally intended url.

The app uses Spring MVC and Acegi security. I know that the problem is session related. Furthermore, if I use the app without via Apache e.g. http://localhost:8085/MyApp it works fine
without any problems. So it seems like the sessions are nto being maintained properly. Any ideas? I'm beginning to think that maybe I should be using mod_proxy (http://docs.codehaus.org/display/JETTY/Configuring+mod_proxy)


11 years ago
Hello,

I have sorted the problem out. This is what was happening: Glassfish has a jar called "webservices-rt.jar" and it contains some of the SOAP stuff. Furthermore, it loads this jar first which means that any subsequest classes that need the classes found in "webservices-rt.jar" then use the already loaded jar classes. In my apps I have "saaj-api-1.3.jar" and "saaj-impl-1.3.jar". I traced the classloader issue by enabling the JVM option -verbose:class and when I made a webservice request in my app I saw something like



I then appended my jars to the server Pre classpath and it now works. So as you can see I've been to Jar Hell and back ;) Happy coding!!
12 years ago
Hi folks,

I have 2 war files which use Spring web services. When I deploy them into Tomcat 5.5 they work fine. However, in Glassfish one of them fails to work. I get the stack trace below. Some discussions on this problem seem to suggest that the xalan classes are interfering with each other but I have not been able to fix it. Any thoughts?

12 years ago
Hello to all,

This is a very strange problem and I hope I can explain it properly. I have two web applications deployed in Glassfish 2.1. Both apps are Spring-based and they use Hibernate. Both are configured via properties files in the classpath. When only one application is deployed all is well and good. However, when the apps are both deployed there is this behaviour:

One of the apps fails because it tries to use the database which does not belong to it i.e. the db that was configured for the other app. So I get a situation where the application is accessing the wrong database and trying to use tables and then failing to find those table well, because it's the wrong db. What could be causing this? Is it a Hibernate issue? The apps work fine in Tomcat. I have verified that both applications are configured using the correct property files when they are deployed.

Please shed some light because I'm going nuts. Anthing will be helpful at this stage ;) Thanks.
12 years ago
Thanks Marco for taking your time to help. I will explore the suggestions which you have raised.

Kind regards,
Ernest
12 years ago
Hello to all,

I have a RMI server running on a Windows box and the client running on a Linux box. The two communicate via the Internet. My problem is that when I
invoke the server from the client for the first time it can take up to 62 seconds for the server to receive the call. I know this because I watch the console and I can tell
exactly when the server receives the call from the client. Subsequent calls take about 6 seconds to reach the server thereafter, which is aceptable.

Why is this happening? Could it be a DNS lookup issue or a process in the RMI system downloading files over the network? I doubt if the problem is related
to client downloading files since the files are tiny anyway. So what could it be?

Thanks for your help in advance.
12 years ago
That sorted it out Rob. Thanks very much. Now I'm confused as to why it worked fine for such a long time and then suddenly broke.
12 years ago
Thanks Rob. I will give it a go and let you know how I get on.
12 years ago

Hello to all,

I have a RMI server application which invokes two external programs in order to complete its task. So I run two external
processes using Runtime.exec(...) and synchronize between the processes. The application has been running fine for over 8
months now but all of a sudden (last week) it broke.

When going through the logs I can see that it's failing to create the two external processes. In fact, I can see from the logs that
the program does create the first external process but the process never returns i.e it does not run the command which has been
fed into Runtime.exec(...).

Now the strange part: the program only fails when it's running as a Windows Service (java-windows-service-wrapper). I'm now running it
from the console and it's fine. It's deployed in a Windows 2003 Server box running Java 6. Has anyone ever experienced such a strange problem
and if so how can I sort it out? I'm sure that something changed in the box to bring about the problem but I just can't seem to figure out what
it is. There is also a Seagate firewall running on the box and at times it can be very hyper-sensitive. It's been installed from the beginning
when the machine was deployed and my program was working fine with it installed so I'm not suspecting the firewall yet.

Please help.

12 years ago
I'm using RMIIO to send a file from a client to the server. My code is as follows:

1. On the client I create a SimpleRemoteInputStream and export it to the server.
2. On the server I read the SimpleRemoteInputStream and save it to a file. That works fine when the firewall is off,
but when the firewall is on then it doesn't. I have been using Wireshark to monitor the port which the server (now the client)
is trying to communicate back with the client (now server) on and each time it's different.


The docs at http://openhms.sourceforge.net/rmiio/faq.html#firewall state that the port that the RMIIO server
exports objects on can be set by setting a system property called com.healthmarketscience.rmiio.exporter.port. I have tried setting
this by doing java -Dcom.healthmarketscience.rmiio.exporter.port=xxxx MyProgram but it does not work.

I am new to RMMIO and I may be missing something. For example the docs state that setting the port only works
when using the "default RemoteStreamExporter." but I'm not even sure if I'm doing that. Can anyone please shed some light?

Thanks,
Ernest

[ October 21, 2008: Message edited by: ernest fakudze ]
[ October 21, 2008: Message edited by: ernest fakudze ]
12 years ago
Thanks for the help folks. I have had to use a Windows application to do this. I invoke it as a Process through Runtime. It seems this is the only way of getting a good result so far as this application uses Powerpoint internally to do the conversion.

Happy New year!!
13 years ago