When I updated SSH Plugin 2.0 to 2.1 and performed a job, the following exception occured.
FATAL: null
java.lang.NullPointerException
at org.jvnet.hudson.plugins.SSHSite.createChannel(SSHSite.java:182)
at org.jvnet.hudson.plugins.SSHSite.executeCommand(SSHSite.java:129)
at org.jvnet.hudson.plugins.SSHBuilder.perform(SSHBuilder.java:60)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:19)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:717)
at hudson.model.Build$BuildExecution.build(Build.java:199)
at hudson.model.Build$BuildExecution.doRun(Build.java:160)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:499)
at hudson.model.Run.execute(Run.java:1502)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:236)
After downgrade to 2.0, it recovered.