Middleware Interview Preparation Guide

In computer science, garbage collection (GC) is a form of automatic memory management. The garbage collector, or just collector, attempts to reclaim garbage, or memory occupied by objects that are no longer in use by the program.

it speeds implementation of distributed applications.
it runs on different platforms
it time independent.
no loss for msg delivery ie gaurenty delivery.

The modes of deploymnet are: Stage,No-stage and External
STAGE: The Administration Server first copies the
deployment unit source files to the staging directories of
target servers specified by the Staging Directory Name
attribute.
The target servers then deploy using their local copy of
the

NOSTAGE: The Administration Server does not copy
deployment unit files. Instead, all servers deploy using
the same physical copy of the deployment files, which must
be directly accessible by the Administration Server and
target servers.
With nostage deployments of exploded archive directories,
WebLogic Server automatically detects changes to a
deployment's JSPs or Servlets and refreshes the deployment.
(This behavior can be disabled if necessary.)

EXTERNAL_stage: The Administration Server does not copy
deployment files. Instead, the Administrator must ensure
that deployment files are distributed to the correct
staging directory location before deployment (for example,
by manually copying files prior to deployment).
With external_stage deployments, the Administration Server
requires a copy of the deployment files for validation
purposes. Copies of the deployment files that reside in
target servers' staging directories are not validated
before deployment.

Thread Dump: When we trigger a thread dump on a application
server,all active thread informations will be dumped into
file whichjis known as thread dump. here, we can get
information about thread like active thread,hung
thread,dead lock,runnable and inactive thread info.
Command : kill -3 PID(Process Id)

Heap Dump: It's snap shot of our JVM's heap memory,so here
we can have all active java objects and their activities
which object doing what and how much memory it is
accupying...

For Windows System,

1. Need to create the key repository using " strmqikm ".
provide the following parameters in the screen which
is opened by the above command,

Key DataBase Type : CMS
File Name : <<File Name>>.kdb
Location Of The File :
<<MQ Root Directory>>\Qmgrs\<<Queue Mana. Name>>\ssl

2. Go to cerficate providers website and get the
Certificate, So that the certificate will be installed
in out machine..

3. The next step is to export the Installed certificate
into the SSL directory.
(<<MQ Root Directory>>\Qmgrs\<<Queue Mana. Name>>\ssl)

Go to Internet Explorer, Tools / Internet Options /
Content / Certificates, From this screen select the
installed Certificate and export the same to the
directory, which is mentioned in the above.

4. Once the export is done, double click on the *.kdb file
and try to import the certificate, which was exported in
the step 3.

1. Assuming u already executed all TN Database scripts.
2. Go to JDBC Pools its divided into 3 parts.
3. in second part u configure the pool and give a name to that pool ex: TN Pool.
4. in first part u find TN Pools edit and associate the TNPool with that. save and restart the server. u can access the TN server from TN console or MWS.

Queue is a data structure which is store the messages.and
every queue has own queue manager.queue manager are
maintaining the all queues.different types of queues are
available in web sphere mq in different purpose.but
generally 4 types of queues r there
1)local queue
2)remote queue
3)alias queue
4)model queue

Cluster is said to be group of queue manager's logically
connected together to balance the load on the remote machine
(i.e if it is remote queue managers which processes your
message). And there are two types of grouping on the queue
managers. 1) Full repository 2) Partial repository. The
full repository queue manager knows all other queue
managers in the cluster and whenever a message comes to it,
and if that is unable to process the message, it will find
a queue in other queue manager in the cluster and ask it to
process the message.

event queues
Open MQ Explorer by selecting Start > Programs > IBM WebSphere MQ > WebSphere MQ Explorer.
Check to see if the depth of the WebSphere® Sensor Events queues is greater than zero.

SDSF (spool Display Search Fecility)