code:
 
create table nt_window_chunks (
  chunk_id serial not null primary key
, window_id int not null references nt_windows on delete cascade on update cascade
);

create table nt_windows (
  window_id serial not null primary key
);
 

code:
 
@Entity
@Table(name = "nt_window_chunks")
public class WindowChunk implements Serializable {
	private static final long serialVersionUID = 1L;
	@Id
	@Basic(optional = false)
	@Column(name = "chunk_id")
	private Integer chunkId;

	@JoinColumn(name = "window_id", referencedColumnName = "window_id")
	@ManyToOne(optional = false, fetch = FetchType.EAGER)
	private Window window;
}

@Entity
@Table(name = "nt_windows")
public class Window implements Serializable {

	private static final long serialVersionUID = 1L;
	@Id
	@Basic(optional = false)
	@Column(name = "window_id")
	private Integer windowId;

	@OneToMany(cascade = CascadeType.ALL, mappedBy = "window", fetch = FetchType.LAZY)
	private List<WindowChunk> chunks;
}
 

code:
 @ManyToOne(fetch = FetchType.LAZY, cascade=CascadeType.ALL)