We're seeing this on at least some test machines running linux x86:

java.io.IOException: Cannot run program "nc": error=2, No such file or directory
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1132)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1075)
at java.lang.Runtime.exec(Runtime.java:624)
at java.lang.Runtime.exec(Runtime.java:448)
at java.lang.Runtime.exec(Runtime.java:345)
at UnixSocketFile.main(UnixSocketFile.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:520)
at com.sun.javatest.regtest.agent.MainActionHelper$SameVMRunnable.run(MainActionHelper.java:218)
at java.lang.Thread.run(Thread.java:804)
Caused by: java.io.IOException: error=2, No such file or directory
at java.lang.ProcessImpl.forkAndExec(Native Method)
at java.lang.ProcessImpl.<init>(ProcessImpl.java:345)
at java.lang.ProcessImpl.start(ProcessImpl.java:276)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1111)
... 11 more