@Override
	public boolean exists(String id) {
		return null != findOne(id);
	}
Job instance repository. It should only return values for Jobs that are deployed.

@author Mark Fisher
@author David Turanski
@author Gunnar Hillert
spring-xd-dirt/src/main/java/org/springframework/xd/dirt/stream/zookeeper/ZooKeeperJobRepository.java