Constantly getting org.hibernate.AnnotationException: @OneToOne or @ManyToOne references an unknown entity: error

I can successfully insert records into the tables using the Db2 console.

INSERT INTO db2admin.school VALUES (1, 'BJS');

INSERT INTO db2admin.STUDENT VALUES (1, 'Pankaj', 30, 1);

I have the following tables.

CREATE TABLE DB2ADMIN.School (school_id SMALLINT PRIMARY KEY NOT NULL, name varchar(128));

create table DB2ADMIN.Student (student_id int PRIMARY KEY NOT null, name varchar(128) not null, age smallint not null, school_id int NOT NULL, FOREIGN KEY (school_id) REFERENCES School(school_id));

One School can contain many students. Here is how I am defining the entity relationships in Hibernate 5.4.18.

@Entity
@Table(name = "school")
public	class	School
{
    @Id
    @SequenceGenerator(name = "SchoolIdSequence", schema="db2admin", sequenceName = "Sequence_School", allocationSize = 1)
    @GeneratedValue(generator = "SchoolIdSequence", strategy = GenerationType.SEQUENCE)
    @Column(name = "SCHOOL_ID")
    private	int id;

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

	@OneToMany(fetch = FetchType.LAZY, cascade=CascadeType.ALL, mappedBy = "school")
	//@JoinColumn(name="student_id", nullable=false)
	private Set<Student> students;

    public School()
    {}

    public School(String name)
    {
    	this.name = name;
    }

    public int getId()
    {
        return id;
    }

    public void setId(int id)
    {
        this.id = id;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }
    
    public Set getStudents()
    {
        return students;
    }
 
    public void setStudents(Set students)
    {
        this.students = students;
    }

    @Override
    public String toString()
    {
        return "School [Name = '" + name + "']";
    }
}

@Entity
@Table(name = "student")
public	class	Student
{
    @Id
    @SequenceGenerator(name = "SequenceStudentId", sequenceName  = "Sequence_Student", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SequenceStudentId")
    @Column(name = "STUDENT_ID")
    private int id;

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

    @Column(name = "AGE")
    private int age;

    @ManyToOne(cascade=CascadeType.ALL, fetch = FetchType.LAZY)
    @JoinColumn(name="school_id", nullable=false)
    private School school;
    
    public Student() 
    {}

    public Student(String name, int age, School school)
    {
        this.name = name;
        this.age = age;
        this.school = school;
    }

    public int getId()
    {
        return id;
    }

    public void setId(int id)
    {
        this.id = id;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }

    public int getAge()
    {
        return age;
    }

    public void setAge(int age)
    {
        this.age = age;
    }

    @Override
    public String toString()
    {
        return "Student [id=" + id + ", Name=" + name + ", Age=" + age + "]";
    }
}

I get the following error on executing the application.

org.hibernate.AnnotationException: @OneToOne or @ManyToOne on org.jfa.persistence.hibernate.entity.Student.school references an unknown entity: org.jfa.persistence.hibernate.entity.School

I have tried to tweak the relationship settings in the class in different ways as suggested by others on Internet/StackOverFlow. Yet, no luck so far. Please help.

You have wrongly referenced school_id instead of student_id in School.java. It should be:

class School
{
   ...

    @OneToMany(fetch = FetchType.LAZY, cascade=CascadeType.ALL)
    @JoinColumn(name="student_id", nullable=false)
    private Set<Student> students;

   ...
}