code: @Override
      public boolean isPersistent() {
  
          final boolean isTraceOn = TraceComponent.isAnyTracingEnabled();
          if (isTraceOn && tc.isEntryEnabled())
              Tr.entry(tc, "isPersistent: " + this);
  
          // Determine if the calling bean is in a state that allows timer service
          // method access - throws IllegalStateException if not allowed.
          checkTimerAccess();
  
          // Determine if the timer still exists; configuration may allow stale data
          checkTimerExists(ALLOW_CACHED_TIMER_IS_PERSISTENT);
  
          if (isTraceOn && tc.isEntryEnabled())
              Tr.exit(tc, "isPersistent: true");
          return true;
      }
docs: Query whether this timer has persistent semantics.
  
  @return true if this timer has persistent guarantees.
  @throws IllegalStateException If this method is invoked while the
  instance is in a state that does not allow access to this
  method.
  @throws NoSuchObjectLocalException If invoked on a timer that has
  expired or has been cancelled.
  @throws EJBException If this method could not complete due to a
  system-level failure.