@Entity
public class Parent {

	@Id @GeneratedValue
	public Long id;
	public String name;

	@OneToMany(cascade = CascadeType.ALL, fetch=FetchType.EAGER)
	@JoinColumn(name = "virtualmachine_id")
	public List<Child> children = new ArrayList<>();
}

@Entity
public class Child {

	@Id
	@GeneratedValue
	public Long id;

	@ElementCollection(fetch=FetchType.EAGER)
	@JoinTable(name = "Child_Properties")
	@MapKeyColumn(name = "key")
	@Column(name = "value")
	public Map<String, String> properties = new HashMap<>();
}

Session session = ...;
Transaction transaction = session.beginTransaction();

Parent parent1 = new Parent();
parent1.name = "Parent 1";

Child child1 = new Child();
child1.properties.put( "some_setting", "a value" );
child1.properties.put( "another_setting", "another value" );
child1.properties.put( "yet_another_setting", "another value" );
parent1.children.add( child1 );

session.persist( parent1 );

transaction.commit();
session.clear();
transaction = session.beginTransaction();

Parent loaded = session.get( Parent.class, parent1.id );
assertEquals( 1, loaded.children.size() ); // <--- Fails; it's 3 instead

transaction.commit();
session.close();