In this section, you will learn to use the "eq" method. This is one of the most important method that is used to apply an "equal" constraint to the named property. 

Hibernate Criteria Expression (eq)

In this section, you will learn to use the "eq" method. This is one of the most important  method that is used to apply an "equal" constraint to the named property.
Expressions: The Hibernate Criteria API supports a rich set of comparison operators. Some standard SQL operators are =, <, ?, >, ?. That supports eq() method in Expression class.
In this tutorial, "Eq" is used with the date object. It takes two parameters e.g. eq("property_name",Object val).
Table Name: insurance

ID	insurance_name	invested_amount	investement_date
2	Life Insurance	25000	0000-00-00 00:00:00
1	Givan Dhara	20000	2007-07-30 17:29:05
3	Life Insurance	500	2005-10-15 00:00:00
4	Car Insurance	2500	2005-01-01 00:00:00
5	Dental Insurance	500	2004-01-01 00:00:00
6	Life Insurance	900	2003-01-01 00:00:00
7	Travel Insurance	2000	2005-02-02 00:00:00

Here is the code of the class using "eq" Expression :

package roseindia.tutorial.hibernate; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Iterator; import java.util.List; import org.hibernate.Criteria; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; import org.hibernate.criterion.Expression; public class HibernateCriteriaQueryExpressionEq {   /**  * @param args  */   public static void main(String[] args) {   // TODO Auto-generated method stub   Session sess = null;   try{   SessionFactory fact = new Configuration().configure().buildSessionFactory();   sess = fact.openSession();   Criteria crit = sess.createCriteria(Insurance.class);   DateFormat format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");   Date date =  (Date)format.parse("2005-01-01 00:00:00");   crit.add(Expression.eq(" investementDate",date));   List list = crit.list();   for(Iterator it = list.iterator();it.hasNext();){   Insurance ins =  (Insurance)it.next();   System.out.println(" Id: " + ins.getLngInsuranceId());   System.out.println(" Insurance Name: " + ins.getInsuranceName());   System.out.println(" Insurance Amount: " + ins.getInvestementAmount());   System.out.println(" Investement Date: " + ins.getInvestementDate());   }   sess.clear();   }   catch(Exception e){   System.out.println(e.getMessage());   }   } }

Output:

log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).log4j:WARN Please initialize the log4j system properly.Hibernate: select this_.ID as ID0_0_, this_.insurance_name as insurance2_0_0_, this_.invested_amount as invested3_0_0_, this_.investement_date as investem4_0_0_ from insurance this_ where this_.investement_date=? Id: 4 Insurance Name: Car Insurance Insurance Amount: 2500 Investement Date: 2005-01-01 00:00:00.0