I set up a VirtualBox slave node in Hudson.

I set the secondary launch method to "Launch slave agents on Unix machines via SSH".

I specified an IP address and username, but no password, since the user doesn't need a password to log in.

I received the following exception:

java.lang.IllegalArgumentException: password argument is null
at com.trilead.ssh2.Connection.authenticateWithPassword(Connection.java:312)
at hudson.plugins.sshslaves.SSHLauncher.openConnection(SSHLauncher.java:512)
at hudson.plugins.sshslaves.SSHLauncher.launch(SSHLauncher.java:168)
at hudson.plugins.virtualbox.VirtualBoxComputerLauncher.delegateLaunch(VirtualBoxComputerLauncher.java:83)
at hudson.plugins.virtualbox.VirtualBoxComputerLauncher.launch(VirtualBoxComputerLauncher.java:67)
at hudson.slaves.SlaveComputer$1.call(SlaveComputer.java:183)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:636)

I'm running Hudson ver. 1.359.