title: Remote call on JNLP4-connect connection failed when running Jenkins slave on Mac
body: <p>The below message is shown in Jenkins console after it runs properly for sometime, I am using macOS High Sierra, with Java version 11 and Jenkins version 2.47.</p>
  
  <p>Any idea what might be wrong?</p>
  
  <pre><code>FATAL: Remote call on JNLP4-connect connection from ‘myMacIP’ failed
      java.lang.NoClassDefFoundError: Could not initialize class hudson.util.ProcessTree$UnixReflection
      at hudson.util.ProcessTree$UnixProcess.kill(ProcessTree.java:575)
      at hudson.util.ProcessTree$UnixProcess.killRecursively(ProcessTree.java:596)
      at hudson.util.ProcessTree$Unix.killAll(ProcessTree.java:517)
      at hudson.Launcher$RemoteLauncher$KillTask.call(Launcher.java:996)
      at hudson.Launcher$RemoteLauncher$KillTask.call(Launcher.java:987)
      at hudson.remoting.UserRequest.perform(UserRequest.java:153)
      at hudson.remoting.UserRequest.perform(UserRequest.java:50)
      at hudson.remoting.Request$2.run(Request.java:336)
      at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:68)
      at java.util.concurrent.FutureTask.run(FutureTask.java:264)
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
          at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
      at hudson.remoting.Engine$1$1.run(Engine.java:94)
      at java.lang.Thread.run(Thread.java:834)
  </code></pre>