The full error is:
java.net.SocketException: Software caused connection abort: recv failed
at java.net.SocketInputStream.socketRead0(Native Method)
a
I couldn't get your exact problem to replicate on my own computer using your code and localhost-connections, but after reading about "BufferedReader.readLine() throwing java.net.SocketException: Software caused connection abort: recv failed" in several different pages, I believe this is related to your network. The connection seems to be terminated due to TCP timeout or data corrupted in the transmission.
If this happens over localhost-connections (server and client in same computer), it could be a faulty memory, otherwise you might have a broken nic, router or cable somewhere along the line. If you're using wireless, they can be pretty unreliable.