java.math.BigInteger cannot be cast to java.lang.Long

Question

I've got List<Long> dynamics. And I want to get max result using Collections. This is my code:

List<Long> dynamics=spyPathService.getDynamics();         Long max=((Long)Collections.max(dynamics)).longValue();  

This is my getDynamics:

public List<Long> getDynamics() {          Session session = null;          session = this.sessionFactory.getCurrentSession();         Query query = session                 .createSQLQuery("SELECT COUNT(*) FROM SpyPath WHERE DATE(time)>=DATE_SUB(CURDATE(),INTERVAL 6 DAY) GROUP BY DATE(time) ORDER BY time;");          List<Long> result = query.list();         return result;      } 

Now I'm getting java.math.BigInteger cannot be cast to java.lang.Long. What's wrong?

Answer 1

Better option is use SQLQuery#addScalar than casting to Long or BigDecimal.

Here is modified query that returns count column as Long

Query query = session              .createSQLQuery("SELECT COUNT(*) as count                              FROM SpyPath                               WHERE DATE(time)>=DATE_SUB(CURDATE(),INTERVAL 6 DAY)                               GROUP BY DATE(time)                               ORDER BY time;")              .addScalar("count", LongType.INSTANCE); 

Then

List<Long> result = query.list(); //No ClassCastException here   

Related link

• Hibernate javadocs
• Scalar queries
• Hibernate.LONG, remember it has been deprecated since Hibernate version 3.6.X
  here is the deprecated document, so you have to use LongType.INSTANCE
• My previous answer

Answer 2

Your error might be in this line:

List<Long> result = query.list(); 

where query.list() is returning a BigInteger List instead of Long list. Try to change it to.

List<BigInteger> result = query.list();