Hibernate query returns list of null

Question

With the following mapping file:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="net.woodenstar.model.shopcenter.GroupItem" table="GROUP_ITEMS">
    <id name="id" type="int">
        <column name="SHC_GIT_ID" />
        <generator class="org.hibernate.id.enhanced.SequenceStyleGenerator">
            <param name="sequence_name">GROUP_ITEMS_SEQUENCE</param>
            <param name="optimizer">none</param>
            <param name="increment_size">1</param>
        </generator>
    </id>
    <property name="name" type="string">
        <column name="SHC_GIT_NAME" length="30" unique="false" not-null="true" />
    </property>
</class>

the model GroupItem is being saved without any hesitation, but when it comes to:

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

the result is a list with the members of null. The dbms is mysql.

UPDATE ONE

the query:

from net.woodenstar.model.shopcenter.GroupItem e  where 1=1  order by e.id

you dont get any errros?

Youcef LAIDANI
– Youcef LAIDANI

2016-07-03 11:27:43 +00:00
Commented Jul 3, 2016 at 11:27 — Youcef LAIDANI
– Youcef LAIDANI, Commented Jul 3, 2016 at 11:27
@YoucefLaidani no, Not errors.

Khoda
– Khoda

2016-07-03 11:28:05 +00:00
Commented Jul 3, 2016 at 11:28 — Khoda
– Khoda, Commented Jul 3, 2016 at 11:28
can you show us your query?

Youcef LAIDANI
– Youcef LAIDANI

2016-07-03 11:29:18 +00:00
Commented Jul 3, 2016 at 11:29 — Youcef LAIDANI
– Youcef LAIDANI, Commented Jul 3, 2016 at 11:29
@YoucefLaidani please read the update.

Khoda
– Khoda

2016-07-03 11:31:20 +00:00
Commented Jul 3, 2016 at 11:31 — Khoda
– Khoda, Commented Jul 3, 2016 at 11:31

JB Nizet · Accepted Answer · 2016-07-03 11:49:23Z

1

What you're looking at is the internal structure of an empty ArrayList. Look at the size. It's 0. This is not a list of nulls. It's an empty list. The list is backed by an array, and since the list is empty, all the elements of the backing array are null.

So, the result you get is perfectly normal: the query just didn't find any matching entity.

answered Jul 3, 2016 at 11:49

JB Nizet

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5 Comments

Khoda Over a year ago

Well, but there is entities on database and every time I run the sql generated by hibernate in console logs directly in mysql, the results just acquired.

JB Nizet Over a year ago

Then either all this data is not committed yet, or your Hibernate app doesn't connect to the same database/schema as the one you use to look at your table.

Khoda Over a year ago

None of the above. saving the entities in database is via application itself. having seen the database with it's own interface (phpMyAdmin) shows committed data.

JB Nizet Over a year ago

Your screenshot shows that you're not looking at the result of query.list(), which is an ArrayList. You're looking at The field entityList of a class named QueryResult. I have no idea what that is. Just do List<GroupItem> result = query.list(); System.out.println(result);.

Anmol Over a year ago

@JB-Nizet List list = qry.list() is returning a list of size 1 with null values. And list==null and list.isEmpty() both returns false. Why ?

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