Java Community | Help. Code. Learn.•4d ago

Cannot invoke "jakarta.persistence.EntityManagerFactory.createEntityManager()" "this.emf" is null

I mapped my classes and transformed it in tables for my database. When I try to create a register I get this error. How I should to initialize emf?

Exception in thread "main" java.lang.NullPointerException: Cannot invoke "jakarta.persistence.EntityManagerFactory.createEntityManager()" because "this.emf" is null
    at org.persistence.RolJpaController.getEntityManager(RolJpaController.java:30)
    at org.persistence.RolJpaController.create(RolJpaController.java:36)
    at org.persistence.PersistenceController.createRol(PersistenceController.java:29)
    at org.logic.LogicController.createRol(LogicController.java:14)
    at org.logic.Main.main(Main.java:16)

Exception in thread "main" java.lang.NullPointerException: Cannot invoke "jakarta.persistence.EntityManagerFactory.createEntityManager()" because "this.emf" is null
    at org.persistence.RolJpaController.getEntityManager(RolJpaController.java:30)
    at org.persistence.RolJpaController.create(RolJpaController.java:36)
    at org.persistence.PersistenceController.createRol(PersistenceController.java:29)
    at org.logic.LogicController.createRol(LogicController.java:14)
    at org.logic.Main.main(Main.java:16)

PersistenceController

package org.persistence;

import jakarta.persistence.EntityManagerFactory;
import jakarta.persistence.Persistence;
import org.logic.Action;
import org.logic.Rol;

public class PersistenceController {

    private static final String PERSISTENCE_UNIT = "IceCreamShopPU";
    private static EntityManagerFactory emf;

    public PersistenceController(){ emf = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT); }

    ActionJpaController ActionJpa = new ActionJpaController(emf);
    FlavorJpaController FlavorJpa = new FlavorJpaController(emf);
    IceCreamJpaController IceCreamJpa = new IceCreamJpaController(emf);
    InvoiceJpaController InvoiceJpa = new InvoiceJpaController(emf);
    OrdenJpaController OrdenJpa = new OrdenJpaController(emf);
    RolJpaController RolJpa = new RolJpaController(emf);
    SizeJpaController SizeJpa = new SizeJpaController(emf);
    UserJpaController UserJpa = new UserJpaController(emf);

    public void createAction(Action act) { ActionJpa.create(act); }

    public void createRol(Rol rol) { RolJpa.create(rol); }

}

package org.persistence;

import jakarta.persistence.EntityManagerFactory;
import jakarta.persistence.Persistence;
import org.logic.Action;
import org.logic.Rol;

public class PersistenceController {

    private static final String PERSISTENCE_UNIT = "IceCreamShopPU";
    private static EntityManagerFactory emf;

    public PersistenceController(){ emf = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT); }

    ActionJpaController ActionJpa = new ActionJpaController(emf);
    FlavorJpaController FlavorJpa = new FlavorJpaController(emf);
    IceCreamJpaController IceCreamJpa = new IceCreamJpaController(emf);
    InvoiceJpaController InvoiceJpa = new InvoiceJpaController(emf);
    OrdenJpaController OrdenJpa = new OrdenJpaController(emf);
    RolJpaController RolJpa = new RolJpaController(emf);
    SizeJpaController SizeJpa = new SizeJpaController(emf);
    UserJpaController UserJpa = new UserJpaController(emf);

    public void createAction(Action act) { ActionJpa.create(act); }

    public void createRol(Rol rol) { RolJpa.create(rol); }

}

9 Replies

JavaBot•4d ago

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Franscis123$#OP•4d ago

LogicController

package org.logic;

import org.persistence.PersistenceController;

public class LogicController {

    PersistenceController PersistenceCtl = new PersistenceController();

    public void createAction (Action act){ PersistenceCtl.createAction(act); }

    public void createRol(Rol rol){ PersistenceCtl.createRol(rol); }

}

package org.logic;

import org.persistence.PersistenceController;

public class LogicController {

    PersistenceController PersistenceCtl = new PersistenceController();

    public void createAction (Action act){ PersistenceCtl.createAction(act); }

    public void createRol(Rol rol){ PersistenceCtl.createRol(rol); }

}

RolJpaController.jav...

Franscis123$#OP•4d ago

Main

package org.logic;

import java.util.Date;

public class Main {

  public static void main (String[] args){

 LogicController LogicCtl = new LogicController();

        Rol role = new Rol("admin", new Date());

        LogicCtl.createRol(role);

}

}

package org.logic;

import java.util.Date;

public class Main {

  public static void main (String[] args){

 LogicController LogicCtl = new LogicController();

        Rol role = new Rol("admin", new Date());

        LogicCtl.createRol(role);

}

}

Rol

package org.logic;

import jakarta.persistence.*;
import java.io.Serializable;
import java.util.Date;
import java.util.Set;

@Entity
@Table(name = "rol")
public class Rol implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @Column(length = 30, unique = true, name = "rol")
    private String rol;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "created_at")
    private Date created_at;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "updated_at")
    private Date updated_at;

    @ManyToMany(mappedBy = "roles")
    private Set<Action> actions;

    public Rol() {}

    public Rol(String rol, Date created_at) {

        this.rol = rol;
        this.created_at = created_at;

    }

    public Long getId() { return id; }

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

    public String getRol() { return rol; }

    public void setRole(String rol) { this.rol = rol; }

    public Date getCreated_at() { return created_at; }

    public void setCreated_at(Date created_at) { this.created_at = created_at; }

    public Date getUpdated_at() { return updated_at; }

    public void setUpdated_at(Date updated_at) { this.updated_at = updated_at; }

    public Set<Action> getActions() { return actions; }

    public void setActions(Set<Action> actions) { this.actions = actions; }

  }

package org.logic;

import jakarta.persistence.*;
import java.io.Serializable;
import java.util.Date;
import java.util.Set;

@Entity
@Table(name = "rol")
public class Rol implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @Column(length = 30, unique = true, name = "rol")
    private String rol;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "created_at")
    private Date created_at;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "updated_at")
    private Date updated_at;

    @ManyToMany(mappedBy = "roles")
    private Set<Action> actions;

    public Rol() {}

    public Rol(String rol, Date created_at) {

        this.rol = rol;
        this.created_at = created_at;

    }

    public Long getId() { return id; }

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

    public String getRol() { return rol; }

    public void setRole(String rol) { this.rol = rol; }

    public Date getCreated_at() { return created_at; }

    public void setCreated_at(Date created_at) { this.created_at = created_at; }

    public Date getUpdated_at() { return updated_at; }

    public void setUpdated_at(Date updated_at) { this.updated_at = updated_at; }

    public Set<Action> getActions() { return actions; }

    public void setActions(Set<Action> actions) { this.actions = actions; }

  }

dan1st•4d ago

What is RolJpa.create(rol)? I think you are using new somewhere where you shouldn't

Franscis123$#OP•4d ago

Its calls to create method from RolJpaController create method. I'm new using JPA, and I watched a tutorials to apply it to my proyect, In its was done like that way.

dan1st•4d ago

Can you show LogicController and main? Did the tutorials you were watching use a DI framework?

Franscis123$#OP•4d ago

No, Its just uses Maven, and me too

dan1st•4d ago

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Cannot invoke "jakarta.persistence.EntityManagerFactory.createEntityManager()" "this.emf" is null

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