Websphere: com.ibm.websphere.management.exception.AdminException: A composition unit with name already exists

When you see error message like this in SystemErr.log of Websphere it shows the application which you are trying to deploy is fully or partially deployed already.If you want to uninstall the app completely. Please delete the application in the following location.

Please stop dmgr .nodeagent and  jvm.In these kind of scenarios mostly app will be missing under applications directory where as it will be present under blas and cus directory.

blas is business level application 

 <Dmgr profile>/config/cells/cellname/applications/appname

<Dmgr profile>/config/cells/cellname/blas/appname
<Dmgr profile>/config/cells/cellname/cus/appname

<Appserver profile >/config/cells/cellname/applications/appname

<Appserver profile>/config/cells/cellname/blas/appname
<Appserver profile>/config/cells/cellname/cus/appname.

Delete the application folder in the above directories.

Delete  wstemp content in both appserver as well as in dmgr.

Restart dmgr and jvm.Try installing your application again.

Error404 class java.lang.ClassNotFoundException: _ibmjsp._login

When login to WAS admin console in IE if you get the below error

An error occurred while processing request:%2Fibm%2Fconsole%2Flogin.jsp

Message:SRVE0200E: Servlet [_ibmjsp._login]: Could not find required class - class java.lang.ClassNotFoundException: _ibmjsp._login.

Its a browser issue .Please clear the cache and try or go for a  different browser.