Null pointer in hibernate result unable to get long value

Question

I'm getting Null Pointer Exception while retrieving Primary Key or Id of an Entity in Hibernate result query. The Primary Key value is simply a long value. My entity class:

@Entity
@Table(name="sample")
public class ccy{

@Id
@column(name = "S_ID")
private long id;

2nd varibale and so on

when i write hibernate query to retrieve it causes Null pointer exception, my select query is:

 long ID = 0;
 String HQL = "select c.id from ccy c where c.name='sowndhar' ";
 Query query = session.createQuery(HQL);
 ID = (Long)query.uniqueResult(); //getting NullPointerException in this    line
 return ID;

Any suggestions plz? Any help would be much appreciated

Obviously query must be null. So you might want to check if something with your session is wrong. Or (as I dont know about hibernate): could it be that you first have to execute your query? It seems a bit suspicious that you create a query; to then immediately try to access its result. Besides: ccy is a really bad name for a class. Should start with uppercase; and: do not abbreviate. Code exists to be read; and such abbreviations dont tell much. — GhostCat
– GhostCat, Commented Mar 20, 2016 at 18:44
Share your complete code where you are creating session and starting transaction. I doubt you have some issue with session. Another point I noticed that you are expecting Unique result from a query without a where clause. If your code worked and there are multiple records, then it will give you org.hibernate.NonUniqueResultException error. Also as already stated, your naming convention is very confusing. — sAm
– sAm, Commented Mar 20, 2016 at 19:02
why should select id from sample return an Long, I would guess that it returns a List of Longs, or du you only have 1 entry in your database? — Raphael Roth
– Raphael Roth, Commented Mar 20, 2016 at 19:37
I think using "sample" in HQL does not work as "sample" is the table name, but HQL needs entity/class name (ccy in your case) — Raphael Roth
– Raphael Roth, Commented Mar 20, 2016 at 19:40

carbontax · Accepted Answer · 2016-03-21 02:46:02Z

1

There are several bad Java practices in your code. By convention class names begin with a capital letter. Variable names begin with a lower case letter. Constants use all caps. Follow the naming conventions.

In the following code I change the type of your variable so that it allows null as a value. I also add some error handling that you will definitely want when requesting a unique result.

By the way, are you sure your session variable is not null? How are you getting it?

    Long id = null; // use the nullable Java type, not the primitive

    String HQL = "select c.id from Ccy c where c.name=:name";

    try {
        // always use parameter tokens in your query ... for security
        Query query = session.createQuery(HQL)
            .setParameter("name", name);

        id = (Long)query.uniqueResult(); 
    } catch (NonUniqueResultException e) {
        // what to do if there are multiple matches
    } catch (NoResultException e) {
        // what if there is no match
    }

    return id;

edited Mar 21, 2016 at 2:46

answered Mar 21, 2016 at 2:39

carbontax

2,18424 silver badges38 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Sowndhar Over a year ago

session I'm getting it from sessionFactory

carbontax Over a year ago

Are you sure that it is not null?

Sowndhar Over a year ago

Yes that is not getting null as i'm injecting sessionFactory using spring dependency injection. Thanks for the help

Collectives™ on Stack Overflow

Null pointer in hibernate result unable to get long value

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related