//define session and transaction
Session session = getSessionFactory().openSession();
Transaction transaction = session.beginTransaction();

//DB query for load all rows
        StringBuffer hql = new StringBuffer();
hql.append("SELECT entity ");
hql.append(" FROM " + Entity.class.getName() + " entity ");
hql.append(" WHERE 1=1 ");
Query query = session.createQuery(hql.toString());

//counter
Integer a = 1;

//scroll
ScrollableResults allItems = query.setCacheMode(CacheMode.IGNORE).scroll(ScrollMode.FORWARD_ONLY);
Map<Long, Entity> itemsId = new HashMap<String, Entity>();

//iterace
while (allItems.next()) {
   
    //work with line
    Entity itemTmp = (Entity)allItems.get(0);
    itemsId.put(itemTmp.getId(),itemTmp);
    session.evict(itemTmp);
   
    //save and clean
    if (a % 200 == 0){
        session.flush();
        session.clear();
    }
    a++;
}

org.springframework.orm.hibernate3.HibernateSystemException: Could not instantiate entity: com.project.Entity; nested exception is org.hibernate.InstantiationException: Could not instantiate entity: com.project.Entity
   at org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:661)
   at org.springframework.orm.hibernate3.HibernateAccessor.convertHibernateAccessException(HibernateAccessor.java:412)
   at org.springframework.orm.hibernate3.HibernateInterceptor.invoke(HibernateInterceptor.java:117)
   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
   at org.springframework.aop.interceptor.AbstractTraceInterceptor.invoke(AbstractTraceInterceptor.java:113)
   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
   at org.springframework.aop.interceptor.AbstractTraceInterceptor.invoke(AbstractTraceInterceptor.java:113)
   at org.springframework.aop.interceptor.DebugInterceptor.invoke(DebugInterceptor.java:61)
   at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
   at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)