The second parameter for SlaveComputer#setChannel(Channel,OutputStream,Channel.Listener) is launchLog.
According to Javadoc of another method, it may be null. " If non-null, receive the portion of data in <tt>is</tt> before the data goes into the binary mode.
If somebody really passes null to that method the underlying 3-argument method will fail with NPE. Although I think that loggers should be always passed, I think that the valid fix would be to have null handling so that API users do not get into the same risk