Hibernate "Column --- cannot be null

Question

I'm using Hibernate in combination with phpmyadmin (MySQL). Recently I found a really weird error. Whenever I try to insert a new row (.persist) I get the following error:

com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Column 'user_id' cannot be null

The error is really obvious. But the weird part is, this error came out of nowhere. I'm ENTIRELY sure the property userId (mapped to 'user_id') isn't null. I tested several times. This is the mapping part: (On the @manytoone part).

  <property name="userId" update="false" insert="false" column="user_id" type="java.lang.Long" />

The OneToMany part isn't the problem I guess.

So the problem here is, i'm 100% sure the value isn't null, still Hibernate passes it as null to the MySQL. (Getter does work).

UPDATE

@ManyToOne side, which causes the error

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
    <class name="xx.xx.xx.AlarmEntity" table="alarms">
        <meta attribute="class-description">
            Hierin staan de object properties van de alarm entiteit.
        </meta>
        <id name="id" type="java.lang.Long" column="id">
            <generator class="native"/>
        </id>
        <property name="keepsRunning"  type="java.lang.Boolean">
            <column name="keeps_running" sql-type="int"></column>
        </property>
        <property name="userId" update="false" insert="false" column="user_id" type="java.lang.Long" />
        <many-to-one name="userAlarm" cascade="save-update" fetch="select" column="user_id" class="xx.xx.xx.UserEntity" />
    </class>
</hibernate-mapping>

Answer 1

Please check the mapping

UserEntity

private int user_id;
private Set<AlarmEntity> alarm;

AlarmEntity

private int alarm_id;
private String keepsRunning;

As per your requirement , I have provided mapping with annotation please check

User

@Id
@Column(name = "userId")
private Long userId;

// parent to Alarm
@Fetch(value = FetchMode.SELECT)
@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name = "userId")
@JsonIgnore 
private List<Alarm> alarmList ;

Alarm

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "alarmId")
private Long alarmId;


@ManyToOne
@JoinColumn(name = "userId", insertable = true, updatable = true, nullable = true)
private User user;

@Column(name="keepsRunning")
private String keepsRunning;