org.hibernate.LazyInitializationException:

[Vas Miriyala]

Dear all I am getting below error when i perform insert operation between two tables.
scenarion:
Table1:Category
Table2:categorycategoryrelation(one to many relationship with category table)
in category table i have a columns id,name and in categorycategoryrelation table i have columns parentcategoryId,childCategoryId and these two id are coming from category table(id)
i am using spring MVC with portlets
this is the error i am getting

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: category.childcategories no session or session was closed

Category.java

@Entity(name="compear_category")
public class Category implements ModelObject, Serializable {
	private static final long serialVersionUID = -3907807779277424923L;

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	@Column(name = "id")
	private Long id;	

    private String name;
    
    private String description;
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getDescription() {
		return description;
	}

	public void setDescription(String description) {
		this.description = description;
	}

	@OneToMany(mappedBy="category", fetch = FetchType.LAZY)
	//@Sort(type = SortType.COMPARATOR, comparator = CategoryProductComparator.class)
	private /*Sorted*/Set<CategoryProductRelation> products;//= new TreeSet<CategoryProductRelation>();//(new CategoryProductComparator());

	@OneToMany(mappedBy="parentCategory", fetch = FetchType.LAZY)
	private Set<CategoryCategoryRelation> parentCategories = new HashSet<CategoryCategoryRelation>();
	
		 
	@OneToMany(mappedBy="childCategory", fetch = FetchType.LAZY)
	@Sort(type = SortType.COMPARATOR, comparator = SequenceComparator.class)
	private SortedSet<CategoryCategoryRelation> childCategories = new TreeSet<CategoryCategoryRelation>();
	
	
	@ManyToOne(fetch = FetchType.EAGER)
	@JoinColumn(name="catalogId")
	private Catalog catalog;
	
	
	@OneToMany(mappedBy = "category", fetch = FetchType.LAZY)
	private Set<CategoryCatalogRelation> catalogs=new HashSet<CategoryCatalogRelation>();
	
	
	private Boolean categoryEnabled;

	
	public Long getId() {
		return id;
	}

	public void setId(Long id) {
		this.id = id;
	}


	public SortedSet<CategoryCategoryRelation> getChildCategories() {
		return childCategories;
	}

	public void setChildCategories(
			SortedSet<CategoryCategoryRelation> childCategories) {
		this.childCategories = childCategories;
	}

	public /*Sorted*/Set<CategoryProductRelation> getProducts() {
		return products;
	}

	public void setProducts(SortedSet<CategoryProductRelation> products) {
		this.products = products;
	}

	public Set<CategoryCategoryRelation> getParentCategories() {
		return parentCategories;
	}

	public void setParentCategories(Set<CategoryCategoryRelation> parentCategories) {
		this.parentCategories = parentCategories;
	}

CategoryCategoryRelation.java

@Entity(name="compear_category_category_relation")
public class CategoryCategoryRelation implements ModelRelation{

	private static final long serialVersionUID = -2519033962309160423L;
	
	
	@Embeddable
	public static class Id implements Serializable {
		
		private static final long serialVersionUID = -970488209304817428L;

		//@Column(name="parentCategoryId")
		private Long parentCategoryId;
		
		
		//@Column(name="childCategoryId")
		private Long childCategoryId;
		
		public Id() {}
		
		public Id( Long parentCategoryId,Long childCategoryId) {
			this.parentCategoryId = parentCategoryId;
			this.childCategoryId = childCategoryId;
		}
		public boolean equals(Object o) {
			if (o != null && o instanceof Id) {
				Id that = (Id)o;
				return this.parentCategoryId.equals(that.parentCategoryId) &&
				this.childCategoryId.equals(that.childCategoryId);
			} else {
				return false;
			}
		}
		public int hashCode() {
			return   parentCategoryId.hashCode()+ childCategoryId.hashCode();
		}
	}

	@EmbeddedId
	private Id id = new Id();
	
	@ManyToOne
	@JoinColumn(name="parentCategoryId",insertable = false,updatable = false)
	private Category parentCategory;

	@ManyToOne
	@JoinColumn(name="childCategoryId",insertable = false,updatable = false)
	private Category childCategory;
	

	public CategoryCategoryRelation() {}
	public CategoryCategoryRelation(Category parentCategory,Category childCategory) {
		this.parentCategory = parentCategory;
		this.childCategory = childCategory;
		
		this.id.parentCategoryId = parentCategory.getId();
		this.id.childCategoryId = childCategory.getId();
		
		parentCategory.getChildCategories().add(this);
		childCategory.getParentCategories().add(this);
	}

	
	public Long getChildId() {
		return childCategory.getId();
	}
	public Long getParentId() {
		return parentCategory.getId();
	}
	
	
	public Category getParentCategory() {
		return parentCategory;
	}
	
	
	public void setParentCategory(Category parentCategory) {
		this.parentCategory = parentCategory;
	}
	
	
	public Category getChildCategory() {
		return childCategory;
	}
	public void setChildCategory(Category childCategory) {
		this.childCategory = childCategory;
	}
		
	
	public Id getId() {
		return id;
	}
	
	public void setId(Id id) {
		this.id = id;
	}

In my controller first I am inserting category into category table and then i am adding child to this category.In my Dao I am using SessionFactory.getCurrentSession() for CRUD oprations
can some one tell me how can i solve this

Database tables:
Category
id(pk)
name
description

CategoryCategoryRelation
parentCategoryId
childCategoryId
both are pk,fk which are refered to id column in category table

[Vas Miriyala]

I found the solution,its very simple,Moved the logic code from Controller to Service Layer,,worked fine,because from Service Layer we are Doing Transaction