Hi I got the Bug and it solved,
Here my bug is I put the code like this
try {
if (getApi().checkSecurePassword((ISession)event.getParameter(SFSEventParam.SESSION),plainpwd,pwd)) {
trace("welcome");
} else {
SFSErrorData errData = new SFSErrorData(SFSErrorCode.LOGIN_BAD_PASSWORD);
errData.addParameter(username);
throw new SFSLoginException(" Password mismatched ", errData);
}
}
catch(Exception e){}
so My Exception block it self catching that SFSLoginException.. so I removed outer try/catch now working fine.