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Showing posts from 2011

WebLogic Admin Console

WebLogic Admin Console
The WebLogic Admin Console is a web-based, user interface used to configure and control a set of WebLogic servers or clusters (i.e. a "domain"). In any logical group of WebLogic servers there must exist one admin server, which hosts the WebLogic Admin Console application and manages the associated configuration files.
WebLogic Administrators will use the Administration Console for a number of tasks, including:
Starting and stopping WebLogic servers or entire clusters.Configuring server parameters, security, database connections and deployed applications.Viewing server status, health and metrics. Note: It is not strictly necessary to use the Weblogic Admin Console to perform these tasks, as they can be scripted using WLST (the WebLogic Scripting Tool).
Accessing the Admin Console
WebLogic Admin Console Url: http://hostname:port/console.
To access the WebLogic Administration Console, assuming the admin server has been started, goto the above url. Where hostname…

JVM detects UTC timezone as ACT

This is a simple symptom-cause-solution blog entry only. I hope these blogs will help fellow administrators.

JVM detects UTC timezone as ACT. This will be evident particularly in web application servers, such as WebLogic, WebSphere and JBoss. Reported time (for example in log files) will not match operating system's time.
JVM tries to determine what the timezone is by looking at operating system settings. It does not recognize the UTC timezone properly and chooses (or defaults to) ACT timezone.
Specify -Duser.timezone=Etc/UTC on the java command-line. This forces the JVM to use the UTC timezone.
Using the tzupdate tool does not appear to rectify the issue.
Note: Some Windows operating systems do not provide a UTC timezone out-of-the-box. A patch is available from Microsoft to rectify this.

WebLogic Interview Questions

In this article I will briefly discuss how I conduct interviews for WebLogic Administration roles.
When conducting interviews I prefer to avoid difficult questions, and instead ask fairly simple questions and look at how well the candidate answers. I would prefer to hire someone who can clearly and concisely explain how to do a simple task than someone who knows every single thing about a particular technology.
I explain at the beginning of the interview, it's acceptable if they are not able to answer every question; I use their answers to help decide if they will be a good fit for the team and the role.
Here are some of the questions I like to ask after I've given them a description of the role on offer.
Non-Technical Questions Which of your previous roles do you think have give you experience that could be important for this role?Tell me what is involved in a typical day in this role?Describe the kind of infrastructure you worked with in this role?On a scale of 1 to 10, with 1 be…

Java System Properties

This is a quick post with some useful code for printing a complete list of Java system properties. System properties give you access to certain JVM startup parameters and system information.
The following code ( can be used to print all system properties.
import java.util.Properties; import java.util.Enumeration;
public class SysProp {
public static void main(String[] args) { Properties sysprops = System .getProperties(); Enumeration e = sysprops.propertyNames(); while (e.hasMoreElements()) { String key = (String)e.nextElement(); String value = sysprops.getProperty(key); System.out.println(key + "=" + value); } }
The resulting output should look like this:
java.vm.vendor.url.bug= 2 Runtime Environment, Standard Edition sun.boot.library.path=E:\APPS\bea_x64\jrockit-R27.5.0-jdk1.5.0_14\jre\bin java.vm.version=R27.5.0-110_o-99226-1.5.0_14-20080528-1505-windows-x86_64 java.vm.vendor=BEA Systems, Inc. java.v…

Connection refused: No available router to destination

This is a simple symptom-cause-solution blog entry only. I hope these blogs will help fellow administrators.

The following exception occurs in WebLogic server logs. Most likely to occur during WebLogic server start-up, but similar exceptions may occur at other times. t3://myserver:8000: Destination unreachable; nested exception is: Connection refused: connect; No available router to destination] at weblogic.jndi.internal.ExceptionTranslator.toNamingException( at weblogic.jndi.WLInitialContextFactoryDelegate.toNamingException( at weblogic.jndi.WLInitialContextFactoryDelegate.getInitialContext( at weblogic.jndi.Environment.getContext( at weblogic.jndi.Environment.getContext(
This message (Connection refused: connect; No available router to destination) is a kind of "catch…