When starting Jenkins on Mac OS X Snow Leopard 10.6.7 and going to the nodes page I get the following exception:

WARNUNG: Failed to monitor master for Freier Swap Space
java.io.IOException: No suitable implementation found: os.name=Mac OS X os.arch=x86_64 sun.arch.data.model=64
at org.jvnet.hudson.MemoryMonitor.obtain(MemoryMonitor.java:60)
at org.jvnet.hudson.MemoryMonitor.get(MemoryMonitor.java:31)
at hudson.node_monitors.SwapSpaceMonitor$MonitorTask.call(SwapSpaceMonitor.java:103)
at hudson.node_monitors.SwapSpaceMonitor$MonitorTask.call(SwapSpaceMonitor.java:99)
at hudson.remoting.LocalChannel.call(LocalChannel.java:45)
at hudson.node_monitors.SwapSpaceMonitor$1.monitor(SwapSpaceMonitor.java:83)
at hudson.node_monitors.SwapSpaceMonitor$1.monitor(SwapSpaceMonitor.java:81)
at hudson.node_monitors.AbstractNodeMonitorDescriptor$Record.run(AbstractNodeMonitorDescriptor.java:202)

Seems that the MemoryMonitor does not work for Mac OS X.