Troubleshooting javax.net.ssl.SSLHandshakeException: Received fatal alert: handshake_failure

Re-published from the Telia Tech Blog. The infamous Java exception javax.net.ssl.SSLHandshakeException: Received fatal alert: handshake_failure is hardly understandable to a mere mortal. What it wants to say is, most likely, something like this: Sorry, none of the cryptographic protocols/versions and cipher suites is accepted both by the JVM and the server. For instance the serverContinue reading “Troubleshooting javax.net.ssl.SSLHandshakeException: Received fatal alert: handshake_failure”

Kioo: How to Troubleshoot Template Processing

So you have created an Om/Reagent/React component using a Kioo template and the result is not as you expected, perhaps just an empty element? Let me share what I have discovered about troubleshooting this (though I am no expert). You will se how to invoke the underlying Clojure function component* manually, how to expand theContinue reading “Kioo: How to Troubleshoot Template Processing”

Inspect Your Webapp in a Live Environment Interactively with GroovyConsole

Have you ever needed to check the state of your webapp’s objects/Session/.. to find out why the hell something doesn’t work or have you had to learn a weird 3rd party API that is only available on the server? Then you were doomed … until the publication of GroovyConsole. JeeUtils GroovyConsole provides a JSP page thatContinue reading “Inspect Your Webapp in a Live Environment Interactively with GroovyConsole”

Troubleshooting logging configuration (Log4j, commons-logging)

Did it ever happen to you that your logging didn’t behave as expected? Here are some tips how to find out what’s going on. Commons-logging (since 1.1) Set the system property org.apache.commons.logging.diagnostics.dest to STDOUT (or STDERR or a file name); docs: -Dorg.apache.commons.logging.diagnostics.dest=STDOUT Extract of a sample output (no commons-logging.properties): Extract of a sample output (incorrectContinue reading “Troubleshooting logging configuration (Log4j, commons-logging)”

Troubleshooting Class/Resource Loading on an Application Server

If you need to find out where is a certain class loaded from or where a class has loaded a resource (typically a configuration file) from, you can use the JSP below – just put it to your web app and point a browser to it. Note: The resource loading tracking assumes that the loadingContinue reading “Troubleshooting Class/Resource Loading on an Application Server”

DB2: Find out current locks, long transactions etc. [snapshot]

To find out current locks in a DB and other information about its current state, you need to take a “snapshot”: db2 “attach to user using ” db2 “get snapshot for applications on ”  > mydatabase_snapshot.txt Look into the resulting mydatabase_snapshot.txt for “Application ID holding”  (if there is a lock, this will read the IDContinue reading “DB2: Find out current locks, long transactions etc. [snapshot]”