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Kyle Willkomm

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Recent posts by Kyle Willkomm

To answer your question David,
The test requires you to know the language syntax heavily. However, to an extent it also requires you to know certain portions of the standard development kit. (I/O, Threads, native types, everythign in java.lang packackage. ect...)
This is unfortunate but true. While it is nice to know how to use the Thread class without looking it up. It should not be necessary to be a certified developer since the documentation on how to use it is readily available in the java docs and knowledge of how to use the language is enough to understandt how to use any standard development class given the javadoc.
Java itself, but especially EJB's and their correcponding Servlets have a reputation of being a bit slow on performance and high on memory usage. Is there anything being done to speed them up? Perhpas moving to a better remote protocol then CORBA or RMI. SOAP would only seem to be slower then CORBA yet considering you have to send descriptions of data along with the data regarding the lookup.
Anyhow, what is the future of the remote bean lookup?
What do you think of Oracle's system of housing the Java right in the database and passing out beans that way?
Oh Heck, there are other large replies here...
Covalent FastStart 3.1 freshly installed
----------------------------------------
./covalent/servers/server-name/conf/httpsd.conf
1)
modify prefork.c tag to be
<IfModule prefork.c>
StartServers 5
MinSpareServers 55
#MinSpareServers 5
MaxSpareServers 250
#MaxSpareServers 10
MaxClients 256
#MaxClients 150
MaxRequestsPerChild 0
</IfModule>

2)
change Apache http request port if needed
Listen 8080
3)
modify Document Root and add matching <Directory> tag with location of ui install
DocumentRoot "/home/willkok/lnie"
<Directory />
Options FollowSymLinks
AllowOverride None
</Directory>
<Directory "/home/willkok/lnie">
</Directory>
4)
to <IfModule mod_jk.c> add these tags with the UI location
#Mount lnie
JkMount /lnie/*.jsp loadbalancer
JkMount /lnie/* loadbalancer
#
# The following line makes apache aware of the location of the /lnie context
#
Alias /lnie /home/willkok/covalent/lnie
<Directory "/home/willkok/covalent/lnie">
<IfModule covalent_usertrack.c>
EnableLocationTracking off
</IfModule>
</Directory>
#
# The following line prohibits users from directly accessing WEB-INF
#
<Directory "/home/willkok/covalent/lnie/WEB-INF/">
AllowOverride None
deny from all
</Directory>
in ./covalent/servers/server-name/conf/workers.properties
1)
change workers.list line to
worker.list=tomcat1,tomcat2,tomcat3,loadbalancer
2)
remove all worker.ajp13 lines
3)
add the following modifying ports as needed
worker.tomcat1.port=8019
worker.tomcat1.host=localhost
worker.tomcat1.type=ajp13
worker.tomcat1.lbfactor=1
worker.tomcat2.port=8029
worker.tomcat2.host=localhost
worker.tomcat2.type=ajp13
worker.tomcat2.lbfactor=1
worker.tomcat3.port=8009
worker.tomcat3.host=localhost
worker.tomcat3.type=ajp13
worker.tomcat3.lbfactor=1
4)
uncomment this line
worker.loadbalancer.type=lb
5)
replace worker.loadbalancer line with
worker.loadbalancer.balanced_workers=tomcat1,tomcat2,tomcat3
copy ./covalent/servers/server-name/conf/server.xml to
./covalent/servers/server-name/conf/server1.xml
./covalent/servers/server-name/conf/server2.xml
./covalent/servers/server-name/conf/server3.xml
1)
in server1.xml modify the shutdown port setting to an open port
<Server port="8015" shutdown="SHUTDOWN" debug="0">
2)
modify the running port setting for an open port
<Connector className="org.apache.ajp.tomcat4.Ajp13Connector"
port="8019" minProcessors="15" maxProcessors="1500"
acceptCount="50" debug="0"/>

3)
add a jvmRoute to the engine tag
<Engine jvmRoute="tomcat1" name="Standalone" defaultHost="localhost" debug="0">

4)
add a context tag for the ui code location below the examples context tag
<Context path="/lnie" docBase="/home/willkok/lnie" />

5)
repeat steps for server2.xml and server3.xml changing port numbers to other values
and the jvmPath to "tomcat2" and "tomcat3" respectivly

copy ./covalent/servers/server-name/bin/tomcat_startup.sh to
./covalent/servers/server-name/bin/tomcat_startup1.sh
./covalent/servers/server-name/bin/tomcat_startup2.sh
./covalent/servers/server-name/bin/tomcat_startup3.sh

1)
in tomcat_startup1.sh
a. Replace all occurences of server.xml with server1.xml
b. Replace all occurences of jvm.stdout with jvm1.stdout
c. Replace all occurences of tomcat.pid with tomcat1.pid
2)
do the same for tomcat_startup2.sh and tomcat_startup3.sh
to start apache and tomcat's
./covalent/servers/server-name/bin/apache_startup.sh start
./covalent/servers/server-name/bin/tomcat_startup1.sh start
./covalent/servers/server-name/bin/tomcat_startup2.sh start
./covalent/servers/server-name/bin/tomcat_startup3.sh start
stop to stop
18 years ago
We use a third party Tomcat install as well by a company called Covalent. I'm not sure if this loab balancing code was written by them or the Tomcat project. I believe it was written by the Tomcat project as part of 4.1. I can e-mail you the instructions but they are too long to post here. I'm not sure if they would work with a regular 4.1 Tomcat or not since I don't know if the load balacing comes with that download or is some thing the Covalent company created and shipped with their version of Apache and Tomcat.
18 years ago
Something I don't see in the index of the book is Tomcat instance clustering. Is it covered? We are running clustered Tomcat instances in production but have done the configuration using 3rd party instructions and a "loadbalancer" class. We would like to fully understand how Tomcat gets clustered and who is doing the balancing. What is means to run multiple JVM's at high volumes on the same platform. How far can it scale on one box? ect... Right now we do not see any scalability improvement from loadbalancing accross a 4th Tomcat instance despite having plenty of OS resources left, CPU, Memory, Bandwith, ect...
18 years ago
Actually I believe there is no cap on the size of a Tomcat response. And WebLogic would not serve an typical servlet response much faster then Tomcat 4.0 would. If this is a third party servlet you are using, would it not be more likely that the servlet has been poorly coded or is simply doing a lot of work. What does this third party servlet do?
18 years ago
Are the lessons learned in this book general and educational enough in style to be applied to Tomcat Servlet Engine, Servlets, and JSP's also. I currently do performance testing of a Tomcat run application on occasion.
I have worked with C++, Smalltalk, Java, Perl, and Python extensivly, I wish I could speak for Ruby as well but I cannot. It may be superior to Python for all I know. What I do know is that if speed and performance is not your issue, Java is twice as simple a language to work with then C++, if only because there are no pointers. That being said, Python is twice as easy as Java. If your project is to be published to thousands of users and is the main focal point of your business, Java is the way to go because of the huge support group, growing reliability and standards, and simplicity over C++. But for any other app I will continue to choose Python. When you download Linux now you get Python, and for good reason, its a wonderful sys admin scripting language. It can do anything Perl can do in a more readable fashion. On a rare occasion Python takes longer to code then Perl its usually because of the wonderful native pattern matching in Perl, but other then that Python will win once you get longer then 30 lines of code every time. Its simply easy to read. But also, CGI scripts are terribly easy as the XML and HTML standard development kit classes are good in Python. I suggest the Zope Application Server for any small web project before turning to Servlets and JSP's for a large application. But this is just one programmer's opinion. If somebody could throw in a Ruby comment I think it would help this thread of commentary.
18 years ago
Hello, I work for a software company that has a lot of business rules to process, these rules change very often and look something like a lot. They are datamapping rules that usually say something like, "this xml tag map's to this EDI field in memory." The rules are written in our own "Business Rule" language and were designed to look like VB. Our server that accepts XML orders from our clients and interprets these rules in order to process a transaction and put it in a form it needs to be to leave our back end. These rules are stored in a database currently and are read into memory when the order processing server starts up. As you can see these rules are not compiled and or, without a doubt, the slowest part of our transaction processing and very CPU intensive. Each order is taking almost 8 CPU seconds each. This is greatly hurting scalability to the point where we can only have about 1 server/thread per CPU. If you do the math that turns out to 7.5 orders/minute per CPU. We aren't going to scale very well at that rate. So I am exploring alternatives. Our current thoughts are to write our server and rules in either Java or Perl. In either case the rules will be able to be compiled or, in the case of Perl, "Professionally Interpreted," well say. Which we assume would be faster then our current home grown interpreter written in C++. My question is, does this seem like a good candidate for Jython? Is Jython thread safe? Would Jython give us what I think it would, a simple clear language to write business rules in, and a free, high quality interpreter to get them compiled and running quickly? I know that was a load of information, thank you for your time.
18 years ago
I was recently asked the question, what are the benefits and drawbacks of using an MVC2 model, specifically Struts, and what are the other options and their benefits. I was able to tell the person what Struts and MVC model give you as benefits but I was unable to tell the person what the drawbacks were, or what other options for web frameworks there are out there. Everybody seems to use this model if they have a complex application. Does anybody know of good alternative frameworks and what their benefits are over Struts? Drawbacks of using Struts?
18 years ago
your Runtime.exe method looks like this public Process exec(String command)
If you hold onto your Process reference, for instance, Process process = Runtime.exe("some command");
You use Process' .waitFor() method to pause until the process finishes. In this example,
process.waitFor();
19 years ago
Thank you very much. That is exactly what I was looking for.
19 years ago
I have always wondered what is the best way to provide the functionality of a "c function". Where you pass in parameters, some computation is done, and you return something. Like public int add(int i, int j) { return i+j; }. Is it better to make a method like that static since it is not really specific to an instance of this object? And, what if there are 100 threads with these objects and they all want to use the method. If it is static will they all try to use the same method and have contention? Or will they all copy the static code and create their own i and j and add them?
19 years ago
I need a classpath to run a browser? There should be no way installing the jdk should break Internet Explorer's ability to load applets. If there is, is that a good idea? Most users of a browser would know nothing about a classpath. Of course most users won't install a JDK but I still think it is a bad idea.
19 years ago
I recently installed the JDK 1.4 latest beta and used it happily for several days. (Not counting my dissapointment at Forte 3.0 failing to run with the new version) I ran into another problem though. I tried to access an applet that used to work for my browser. I would send the example but it is a company internal applet. The applet got a class def not found error and simply didn't load. I uninstalled JDK 1.4 and I assume my Internet Explorer reverted back to its default engine and the applet in question was again able to run. Is this a problem we are going to see with many applets and backwards compatability?
19 years ago