getSamples.java

	@Override
	public Set<Sample> samplesFromGroups(Collection<Long> ids) {
		return repository.findAllByIdIn(ids) // get all groups
				.stream()
				.map(Group::getSamples) // get samples of each group
				.flatMap(Set::stream) // flatten into a single set of samples
				.collect(toSet());
	}
	
	@Override
	public Set<Sample> samplesFromGroups(Collection<Long> ids) {
		return repository.findAllByIdIn(ids) // get all groups
				.stream()
				.map(group -> group.getSamples()) // get samples of each group
				.flatMap(Set::stream) // flatten into a single set of samples
				.collect(toSet());
	}

	@Override
	public Set<Sample> samplesFromGroups(Collection<Long> ids) {
		return repository.findAllByIdIn(ids) // get all groups
				.stream()
				.map(new Function<Group, Set<Sample>>() {
					@Override
					public Set<Sample> apply(Group group) {
						return group.getSamples();
					}
				}) // get samples of each group
				.flatMap(Set::stream) // flatten into a single set of samples
				.collect(toSet());
	}