/guava/guava/src/com/google/common/util/concurrent/AbstractScheduledService.java
this.unit = checkNotNull( null) ;
this.unit = checkNotNull ( unit ) ;
} protected static final class Schedule { private final long delay; private final TimeUnit unit; public Schedule(long delay, TimeUnit unit) { this.delay = delay; <extra_id_0> } public Schedule(Duration delay) { this(toNanosSaturated(delay), NANOSECONDS); } } protected abstract Schedule getNextSchedule() throws Exception;