Programming: Java

I had to build mod_jk.so (The Tomcat Java App Server <--> Apache Web Server connector) at work for Solaris. The instructions in the documentation do not work under Solaris, so I figured I'd detail my findings for future use.Go get the Java 2 SDK for Solaris (if you don't have it) - If you're not root, don't worry, it still installs fine.Make sure JAVA_HOME environment variable is set to the directory that the Java SDK is located in (ex /usr/local/jdk1.3.1, or /home/joe/jdk1.3.1)Make sure $JAVA_HOME/bin is part of your PATH.You MUST have the Tomcat SOURCE (A binary Tomcat install does NOT have these files)Go to tomcat_source/src/native/Apache1.3 (Note that you will NOT be using the Makefile to do this!)Run the following two commands. (Change the location of apxs as appropriate)/usr/local/apache/bin/apxs -I$JAVA_HOME/include -I$JAVA_HOME/include/solaris -I ../jk -o mod_jk.so -c *.c ../jk/*.cgcc -shared -lposix4 -o mod_jk.so *.oYou are done! You have a working Solaris mod_jk.so! :) Copy it to the /libexec directory under your Apache directory, then head to the Tomcat docs for info on setting up Tomcat and Apache to work together.

In order to debug an problem involving an application that uses Jrun, you will need to use the Jrun logs.  Not only do these log files give you evidence of how Jrun is performing, they can also reflect issues "upstream" from Jrun, such as errors from the JAD, TAD, or the mainframe.In /logs/Jrun, you will find two types of files, each with a date/timestamp extension so files don't overwrite each other or get impossibly (versus merely obnoxiously) long.  They are stdoutmmddyy-hhmmss.log and stderrmmddyy-hhmmss.log, where mmddyy-hhmmssis the date and timestamp of when the logfile was first opened.  Jrun will open a new logfile whenever (a) Jrun is restarted or (b) a new servlet is loaded by the Java virtual machine.  stdout is the most useful file, as it contains timestamps and error messages.  stderr contains some error messages, but since it doesn't have timestamps, it is difficult to correlate the messages to a specific problem.  If you want to see when Jrun was stopped and restarted, you can view /software/jrun/jsm-default/logs/event.log; in this file, you will find a log showing when Jrun was stopped or restarted.  This file can be useful when trying to determine what someone else may have done to attempt to restart Jrun.When reviewing the log files on each server, the OS date/timestamp of the file will indicate when that file was last updated.  If Jrun was merelyswitching filenames, you should see another file with a date/timestamp in the filename that is within seconds of when the last file was closed out.  If you see a large gap ...

An Introduction to Java Stack Traces By Calvin Austin July 1998 It's the night before your product release. You run your final tests and then it happens--you get a JavaTM stack trace. You look through your Java programming books, but this seems to be an area that's missing! Well no need to panic, just follow the simple steps suggested here and you'll be home before midnight! This article shows you step by step how to recognize and collect the clues in a stack trace to solve your Java software problems. What is a Java stack trace? A Java stack trace is a user-friendly snapshot of the threads and monitors in a Java1 Virtual Machine (JVM). Depending on how complex your application or applet is, a stack trace can range from fifty lines to thousands of lines of diagnostics. However, regardless of the size of the stack trace there are a few key things that anyone can find to help diagnose most Java software problems, whether you are a Java programming expert or very new to the Java platform. How are Java Stack Traces Generated? There are three popular ways to generate a Java stack trace: sending a signal to the Java Virtual Machine; the Java Virtual Machine generates a stack trace for you; or using debugging tools or Java API calls. Sending a signal to the Java Virtual Machine On UNIX platforms you can send a signal to a program by using the kill command. This is the quit signal, which is handled ...

While this example is for ColdFusion, it looks more like marketing demanded that their code sample had to use at least some ColdFusion dependancies. The only thing actually calling ColdFusion-specific functionality is the setting of three global variables, which can easily be done using the language of your choice. The rest of the example is built using JavaScript, so it looks nearly effortless to get the ColdFusion variables out of the way.