IllegalArgumentException - Hibernate Error - org.hibernate.hql.internal.ast.QuerySyntaxException: Clasa is not mapped [SELECT c FROM Clasa c]

I have the following line of code, in which I'm trying to get all users from a class, by using JPQL syntax:
`

import javax.persistence.EntityManager;
import javax.persistence.TypedQuery;
import java.util.List;
public class ClasaDao {
private EntityManager em;
public ClasaDao(EntityManager em){
this.em = em;
}
public List<Clasa> getClase(){
String sql = "SELECT c FROM Clasa c";
TypedQuery<Clasa> query = em.createQuery(sql, Clasa.class);
return query.getResultList();
}
public void stergeClasa(Clasa clasa){
clasa = em.merge(clasa);
em.remove(clasa);
}}`

and this is the Entity class:

    import javax.persistence.*;
import java.io.Serializable;
import java.util.Date;
import java.util.List;
@Entity
@Table(name = "Clasa")
public class Clasa implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
@Temporal(value = TemporalType.DATE)
private Date dataIncepere;
private String nume;
@ManyToOne
private Curs curs;
@ManyToMany(mappedBy = "clasa")
private List<Student> student;
public List<Student> getStudent() {
return student;
}
public void setStudent(List<Student> student) {
this.student = student;
}
public Clasa getClasa() {
return clasa;
}
public void setClasa(Clasa clasa) {
this.clasa = clasa;
}
private Clasa clasa;
public Curs getCurs() {
return curs;
}
public void setCurs(Curs curs) {
this.curs = curs;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public Date getDataIncepere() {
return dataIncepere;
}
public void setDataIncepere(Date dataIncepere) {
this.dataIncepere = dataIncepere;
}
public String getNume() {
return nume;
}
public void setNume(String nume) {
this.nume = nume;
}
@Override
public String toString() {
return "Clasa{" +
"dataIncepere=" + dataIncepere +
", nume='" + nume + '\'' +
'}';
}
}

The lines above yield the following error: Exception in thread "main" java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: Clasa is not mapped [SELECT c FROM Clasa c]

Any ideas as to what might be causing this error will be greatly appreciated

It seems that:

@ManyToMany(mappedBy = "clasa")

should be rather:

@ManyToMany(mappedBy = "Clasa")

This may be causing the IllegalArgumentException.

If it says it's not mapped, then the class is not included in the persistence unit. Check you persistence.xml if you listed the class there or maybe add <exclude-unlisted-classes>false</exclude-unlisted-classes>