This sounds to be an issue reading the local file than a problem with the hdfs client. The stack trace shows a problem reading the local file that has bubbled all the way up. The lease is dropped because the client has dropped the connection due to the IOException while reading the file.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.