A Dictionary of unusual Java Exceptions

Exception # 1:
The transaction service encountered an error on an xa_recover operation. The resource was com.ibm.ws.rsadapter.spi.WSRdbXaResourceImpl@510051. The error code was XAER_RMERR. The exception stack trace follows: javax.transaction.xa.XAException

Description:
The XA transaction manager tries to recover for an early server crash either in application server or database server side or could be both but the user id that has been used to connect to the database doesn't have the permission to access certain tables.

Solution:
provide access to the BA_PENDING_TRANSACTIONS table for the particular database user in question

Exception # 2:
Exception in thread "CompilerThread0" java.lang.OutOfMemoryError: requested 32776 bytes for Chunk::new. Out of swap space?

Description:
Websphere Application Server 6.1.17 goes OutOfMemory with the above error trace on the console

Solution:
This is bug in JVM JIT compilation and the fix is not confirmed yet. The work around is to use below configuration:

-XX:+UseDefaultStackSize -Xss256K

Resources:
http://www.ibm.com/developerworks/websphere/library/techarticles/0407_woolf/0407_woolf.html- Distributed transaction in WAS (Exception # 1)
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4916142 - OutOfMemory Error (Exception # 2)

Clear Case concepts

#1 Clear Case merge

Merge on clear case Diff Merge tools might look confusing at times. Here are 2 scenarios of merging on Diff Merge.

Rebase:

1st window is the base window which contains the version of the file from which the change was made. The changes, made by other and delivered to integration stream, are shown on the 2nd window. And the 3rd window shows the Development stream to which you'd rebase.

Deliver:

1st window is the base window which contains the version of the file from where you've started work on the file and made necessary changes. 2dn window shows the changes now you've in your development stream. And the 3rd window shows Integration stream to which you're going to deliver your changes.

Resources:

http://clearcase.weintraubworld.net/ - not-so-official clear case website
http://clearcase.weintraubworld.net/cc.branch.html#real - Branching theory of clear case
http://clearcase.weintraubworld.net/cc.branch2.html - Branching strategy

Useful ClearCase commands

Frequently used cleartool commands:

List out the checked out files
cleartool> lsco

Check in a file
cleartool>ci [-nc] filename

Check out a file
cleartool>co filename

Undo a check out
cleartool>unco filename

Add a file to source control
cleartool>mkelem filename


Resources:

http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi?cmd=getdoc&coll=0530&db=man&fname=1%20cleartool - Contains list of commands
http://www.ibm.com/developerworks/rational/library/836.html - cheat sheet