Generic DAO in Hibernate interface and abstract implementation

AbstractGenericDao.java

package com.bytestree.dao;

import java.io.Serializable;
import java.lang.reflect.ParameterizedType;
import java.util.List;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.criterion.Example;
import org.springframework.beans.factory.annotation.Autowired;

@SuppressWarnings("unchecked")
public abstract class AbstractGenericDao<E> implements GenericDao<E> {

	private final Class<E> entityClass;

	public AbstractGenericDao() {
		this.entityClass = (Class<E>) ((ParameterizedType) this.getClass().getGenericSuperclass())
				.getActualTypeArguments()[0];
	}
	
	@Autowired
	private SessionFactory sessionFactory;

	protected Session getSession() {
		return this.sessionFactory.getCurrentSession();
	}

	@Override
	public E findById(final Serializable id) {
		return (E) getSession().get(this.entityClass, id);
	}

	@Override
	public Serializable save(E entity) {
		return getSession().save(entity);
	}

	@Override
	public void saveOrUpdate(E entity) {
		getSession().saveOrUpdate(entity);
	}

	@Override
	public void delete(E entity) {
		getSession().delete(entity);
	}

	@Override
	public void deleteAll() {
		List<E> entities = findAll();
		for (E entity : entities) {
			getSession().delete(entity);
		}
	}

	@Override
	public List<E> findAll() {
		return getSession().createCriteria(this.entityClass).list();
	}

	@Override
	public List<E> findAllByExample(E entity) {
		Example example = Example.create(entity).ignoreCase().enableLike().excludeZeroes();
		return getSession().createCriteria(this.entityClass).add(example).list();
	}

	@Override
	public void clear() {
		getSession().clear();

	}

	@Override
	public void flush() {
		getSession().flush();

	}
	 
}

GenericDao.java

package com.bytestree.dao;

import java.io.Serializable;
import java.util.List;

/**
* Interface to provide common DAO methods
* 
*/

public interface GenericDao<E>
{

	/**
	* 
	* @param entity: entity to save
	* @return Identifier of saved entity
	*/
	Serializable save(E entity);
	
	/**
	* 
	* @param entity:entity to save or update
	*/
	public void saveOrUpdate(E entity);
	
	/**
	* 
	* @param entity: entity to delete
	*/
	void delete( E entity );
	
	/**
	* Delete all records
	*/
	void deleteAll();
	
	/**
	* Find all records
	* @return
	*/
	List<E> findAll();
	
	/**
	* Find all records matching provided entity
	* @param entity: entity object used for search
	* @return
	*/
	List<E> findAllByExample( E entity );
	
	/**
	* Find by primary key
	* @param id
	* @return unique entity 
	*/
	E findById( Serializable id );
	
	/**
	* Clear session
	*/
	void clear();
	
	/**
	* Flush session
	*/
	void flush();

}