Websphere tutorial

In general we need thread dump and heap dump mainly to find the Out Of Memory exception Thread dump :- a snapshot of live running java threads in the application server                       KILL -3 <PID>   to generate a thread dump The other way and in real-time we use                     Java\jdk1.8.0_201\bin\jstack <pid> > file.out Heap dump :- a snapshot of live running java objects in the heap memory 1. Click Servers > Application servers in the administrative console navigation tree. 2. Click server_name >Runtime Performance Advisor Configuration. 3. Click the Runtime tab. 4. Select the Enable automatic heap dump collection checkbox. 5. Click OK. Provided a simple answer. If any doubts regarding it, post a comment.

Generally in trouble shooting mainly we concentrate on 1)Log files 2)Hung threads 3)OOM(OutOfMemory) 4)CPU starvation 5)Disk space issues 6)Web container issues Log Files Application Server ----> jvm logs -----------> SystemOut.log (Start,Stop,Application processes)                                                       -----------> SystemErr.log (server related errors)                                                               -----> ProcessLogs ------> NativeStdOut.log (Sun jdk related memory,GC,etc.,)                                               ...

1. tar command examples Create a new tar archive. $ tar cvf archive_name.tar dirname/ Extract from an existing tar archive. $ tar xvf archive_name.tar View an existing tar archive. $ tar tvf archive_name.tar   2. grep command examples Search for a given string in a file (case in-sensitive search). $ grep -i "the" demo_file Print the matched line, along with the 3 lines after it. $ grep -A 3 -i "example" demo_text Search for a given string in all files recursively $ grep -r "ramesh" * 3. find command examples Find files using file-name ( case in-sensitve find) # find -iname "MyCProgram.c" Execute commands on files found by the find command $ find -iname "MyCProgram.c" -exec md5sum {} \; Find all empty files in home directory # find ~ -empty 4)ls command examples Display filesize in human readable format (e.g. KB, MB etc.,) $ ls -lh -rw-r----- 1 ramesh team-dev 8.9M Jun 12 15:27...

Interview questions and also find the realtime usage commands link at the end of the blog. Which will be helpful during the interview. In a Web-based architecture, if you try to hit the URL, it shows an error like page cannot be displayed, How to troubleshoot this issue? Ans: The Flow of Request happens from Load Balancer >> Webserver >> Appserver >> DBso the investigation for such issues should also follow the same routes .. ( well thats how i follow ) Try to check if the url is responding from your end. (This will eliminate if its specific to a user or its error for every one) Check the Webserver if its running or not, If it’s not running start it Check if the application server and application is running.. if not start it Try to access the Application directly from the Appserver .. ie using the http transport port. ie wc_defalut .. ( this will identify if the error is due to App server or is with the Webserver/plugin) check for the e...