why we go from bottom to top while debugging a log file messages

[Mathew Lee]

hi,

I am debugging some erros within in websphere 6.0 server within the error log files.

I came to know for debugging error say following error

  
om.ibm.ws.tcp.channel.impl.WorkQueueManager.workerRun(WorkQueueManager.java(Compiled Code))
[9/17/09 14:32:27:578 CDT] 0000003f SystemErr     R  at com.ibm.ws.tcp.channel.impl.WorkQueueManager$Worker.run(WorkQueueManager.java(Compiled Code))
[9/17/09 14:32:27:578 CDT] 0000003f SystemErr     R  at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java(Compiled Code))
[9/17/09 14:48:28:141 CDT] 00000042 SystemErr     R xyz.abc.def.exception.BaseException: 

 at xyz.abc.def.ServiceImpl.methodA(ServiceImpl:223)
 at yz.abc.def.SecureDelegate.methodB(SecureDelegate:197)
 at xyz.abc.def.BaseBean.methodC(BasseBean:112) 
 at xyz.abc.def.ServicesAuthBean.serviceAuthSave(ServicesAuthBean.java:123)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java(Compiled Code))


  

l need to go from bottom to top to understand the flow, issue like
class ServicesAuthBean calling ...BaseBean calling....SecureDelegate calling....ServiceImpl

I though it other way like
class ServiceImpl calling ...SecureDelegate calling...BaseBean calling...ServicesAuthBean

Please clarify how to debug and how to understand thousands of lines of log files

I am bit new to debugging world.
Any ideas, suggestions, ideas, links highly appreciated. Thanks in advance.

[Balu Sadhasivam]

Its actually a combination of both. First go to bottom and search updwards for error and the once you found walk downwards to find the application logic flow.

Well what if your log is weeks old , bottom logs shows up the latest log. I usually prefer opening log in a window and mark the cursor , and test the scenario in another window and watch the logs flow. First Grep (find) for "Error" , "Exception" to make sure there is nothing serious to look for.
Then grab a line where you could relate and walk downwards from there.

(but Unix is cool , Shift f and you are there)

[Campbell Ritchie]

Too difficult for "beginning Java". Moving.