How to map a weak entity in Spring Boot and Java persistence

Edited (9/30/20): The table in MySQL is displayed as it follows:

I have a entity called UbicacionPlanta (UbicateFloor in English), weak entity of Departamento (Department in English). The structure is the following:

@Entity(name = "ubicaciones_plantas")
@Table
public class UbicacionPlanta implements Serializable {

    @Id
    @JoinColumn(name = "iddepartamento", referencedColumnName = "iddepartamento", nullable = false)
    @OneToMany
    @JsonInclude(JsonInclude.Include.NON_NULL)
    private Departamento departamento;

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

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

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

    public Departamento getDepartamento() {
        return departamento;
    }
//Getters and Setters

}

Intellij IDEA give an error like this:

Regarding DTO, the class is implemented like:

public class MUbicacionPlanta {

    private String departamentoId;

    private Long idubicacion;

    private String abreviacion_ubicacion;

    private String descripcion_ubicacion;

    public MUbicacionPlanta(UbicacionPlanta ubicacionPlanta) {
        this.departamentoId = ubicacionPlanta.getDepartamento().getIddepartamentos();
        this.idubicacion = ubicacionPlanta.getIdubicacion();
        this.abreviacion_ubicacion = ubicacionPlanta.getAbreviacion_ubicacion();
        this.descripcion_ubicacion = ubicacionPlanta.getDescripcion_ubicacion();
    }
    //Getters and Setters
}

How can I do in order to integrate the ids for weak entity, please?

Thanks to this question: https://stackoverflow.com/questions/29760730/how-to-mapping-an-onetomany-relation-with-weak-entity-in-hibernate

Departamento (Department) is implemented like this:

@Entity(name = "departamentos")
@Table
public class Departamento implements Serializable {

    @Id
    @Size(max = 50)
    @Column(name = "iddepartamentos")
    private String iddepartamentos;

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

    @JoinColumn(name = "sede_departamento", referencedColumnName = "sede_departamento", nullable = false)
    @ManyToOne
    private Sede sede;

    @OneToMany(mappedBy="departamentos")
    private Set<UbicacionPlanta> ubicacionPlantas;
    
    //Constructor, getters and setters

}

And UbicacionPlanta (UbicateFloor), as it follows:

@Entity(name = "ubicaciones_plantas")
@Table
public class UbicacionPlanta implements Serializable {


    @JoinColumn(name = "iddepartamento", referencedColumnName = "iddepartamento", nullable = false)
    @ManyToOne
    private Departamento departamento;

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

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

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

    //Constructor, getters and setters
}