### Question:
EventBuilder { public EventBuilder clear(String key) { instanceNode.remove(key); return this; } private  EventBuilder(ObjectId objectId, long migrationEventId, TenantId tenantId, Id actorId, Id userId, EventVerb eventVerb); private  EventBuilder(ObjectId objectId, TenantId tenantId, Id actorId, Id userId, EventVerb eventVerb); static EventBuilder create(ObjectId id, TenantId tenantId, Id userAndActorId); static EventBuilder create(IdProvider idProvider, String className, TenantId tenantId, Id userAndActorId); static EventBuilder create(IdProvider idProvider, String className, TenantId tenantId, Id actorId, Id userId); static EventBuilder update(ObjectId objectId, TenantId tenantId, Id userAndActorId); static EventBuilder update(ObjectId objectId, TenantId tenantId, Id actorId, Id userId); static EventBuilder migrate(ObjectId objectId, long migrationEventId, TenantId tenantId, Id userAndActorId); static EventBuilder migrate(ObjectId objectId, long migrationEventId, TenantId tenantId, Id actorId, Id userId); ObjectId getObjectId(); EventBuilder delete(String key); EventBuilder clear(String key); EventBuilder set(String key, V value); EventBuilder setTrackEventProcessedLifecycle(Boolean trackEventProcessedLifecycle); Event build();  }### Answer:
@Test public void testClear() throws Exception { JsonEventConventions jec = new JsonEventConventions(); IdProviderImpl idProvider = new IdProviderImpl(new OrderIdProviderImpl(new ConstantWriterIdProvider(100))); EventBuilder eventBuilder = EventBuilder.create(idProvider, EventBuilderTest.class.getSimpleName(), tenantId, actorId); eventBuilder.set("key", "value"); Event has = eventBuilder.build(); ObjectNode hasNode = jec.getInstanceNode(has.toJson(), EventBuilderTest.class.getSimpleName()); Assert.assertTrue(hasNode.has("key")); eventBuilder.clear("key"); Event hasNot = eventBuilder.build(); ObjectNode hasNotNode = jec.getInstanceNode(hasNot.toJson(), EventBuilderTest.class.getSimpleName()); Assert.assertFalse(hasNotNode.has("key")); }