code: @NullSafe
    public static boolean isRunnable(Thread thread) {
      return (thread != null && Thread.State.RUNNABLE.equals(thread.getState()));
    }
docs: Determines whether the specified Thread is a runnable Thread.  A "runnable" Thread is any Thread that can be
  scheduled by the Operating System (OS) for execution.
  
  @param thread the Thread to evaluate.
  @return a boolean value indicating whether the Thread is in a runnable state.
  @see java.lang.Thread#getState()
  @see java.lang.Thread.State#RUNNABLE