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Franscis123$#

•Created by Franscis123$# on 2/18/2025 in #java-help

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); }

}

14 replies

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•Created by Franscis123$# on 2/3/2025 in #java-help

The collection of metamodel types is empty

I'm have a maven project with JPA and EclipseLink. When I run it don't generate the tables in the database. I have this output:

The collection of metamodel types is empty. Model classes may not have been found during entity search for Java SE and some Java EE container managed persistence units.  Please verify that your entity classes are referenced in persistence.xml using either <class> elements or a global <exclude-unlisted-classes>false</exclude-unlisted-classes> element

The collection of metamodel types is empty. Model classes may not have been found during entity search for Java SE and some Java EE container managed persistence units.  Please verify that your entity classes are referenced in persistence.xml using either <class> elements or a global <exclude-unlisted-classes>false</exclude-unlisted-classes> element

IceCreamShop/src/main/resources/META-INF/persistence.xml:

<?xml version="1.0" encoding="UTF-8"?>
<
persistence version="3.2" xmlns="https://jakarta.ee/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="https://jakarta.ee/xml/ns/persistence https://jakarta.ee/xml/ns/persistence/persistence_3_2.xsd">
  <persistence-unit name="IceCreamShopPU" transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <class>org.logic.Action</class>
    <class>org.logic.Flavor</class>
    <class>org.logic.Ice_Cream</class>
    <class>org.logic.Invoice</class>
    <class>org.logic.Orden</class>
    <class>org.logic.Role</class>
    <class>org.logic.Size</class>
    <class>org.logic.User</class>
    <properties>
      <property name="jakarta.persistence.jdbc.url" value="jdbc:mariadb://localhost:3306/IceCream?serverTimezone=UTC"/>
      <property name="jakarta.persistence.jdbc.user" value="admin"/>
      <property name="jakarta.persistence.jdbc.driver" value="org.mariadb.jdbc.Driver"/>
      <property name="jakarta.persistence.jdbc.password" value="+V$u]"/>
      <property name="jakarta.persistence.schema-generation.database.action" value="create"/>
    </properties>
  </persistence-unit>
</persistence>

<?xml version="1.0" encoding="UTF-8"?>
<
persistence version="3.2" xmlns="https://jakarta.ee/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="https://jakarta.ee/xml/ns/persistence https://jakarta.ee/xml/ns/persistence/persistence_3_2.xsd">
  <persistence-unit name="IceCreamShopPU" transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <class>org.logic.Action</class>
    <class>org.logic.Flavor</class>
    <class>org.logic.Ice_Cream</class>
    <class>org.logic.Invoice</class>
    <class>org.logic.Orden</class>
    <class>org.logic.Role</class>
    <class>org.logic.Size</class>
    <class>org.logic.User</class>
    <properties>
      <property name="jakarta.persistence.jdbc.url" value="jdbc:mariadb://localhost:3306/IceCream?serverTimezone=UTC"/>
      <property name="jakarta.persistence.jdbc.user" value="admin"/>
      <property name="jakarta.persistence.jdbc.driver" value="org.mariadb.jdbc.Driver"/>
      <property name="jakarta.persistence.jdbc.password" value="+V$u]"/>
      <property name="jakarta.persistence.schema-generation.database.action" value="create"/>
    </properties>
  </persistence-unit>
</persistence>

32 replies

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•Created by Franscis123$# on 1/30/2025 in #java-help

No Persistence provider for EntityManager named IceCreamShopPU

Jan 30, 2025 9:51:12 AM jakarta.persistence.spi.PersistenceProviderResolverHolder$DefaultPersistenceProviderResolver log
WARNING: jakarta.persistence.spi::No valid providers found.
Exception in thread "main" jakarta.persistence.PersistenceException: No Persistence provider for EntityManager named IceCreamShopPU
    at jakarta.persistence.Persistence.createEntityManagerFactory(Persistence.java:96)
    at jakarta.persistence.Persistence.createEntityManagerFactory(Persistence.java:66)
    at org.persistence.ActionJpaController.<init>(ActionJpaController.java:17)
    at org.persistence.PersistenceController.<init>(PersistenceController.java:5)
    at org.logic.Main.main(Main.java:9)

Jan 30, 2025 9:51:12 AM jakarta.persistence.spi.PersistenceProviderResolverHolder$DefaultPersistenceProviderResolver log
WARNING: jakarta.persistence.spi::No valid providers found.
Exception in thread "main" jakarta.persistence.PersistenceException: No Persistence provider for EntityManager named IceCreamShopPU
    at jakarta.persistence.Persistence.createEntityManagerFactory(Persistence.java:96)
    at jakarta.persistence.Persistence.createEntityManagerFactory(Persistence.java:66)
    at org.persistence.ActionJpaController.<init>(ActionJpaController.java:17)
    at org.persistence.PersistenceController.<init>(PersistenceController.java:5)
    at org.logic.Main.main(Main.java:9)

ActionJpaController:

package org.persistence;

import jakarta.persistence.*;
import java.io.Serializable;
import jakarta.persistence.criteria.CriteriaQuery;
import jakarta.persistence.criteria.Root;
import org.logic.Role;
import java.util.ArrayList;
import java.util.List;
import org.logic.Action;
import org.persistence.exceptions.NonexistentEntityException;

public class ActionJpaController implements Serializable {

    public ActionJpaController(EntityManagerFactory emf) { this.emf = emf; }

    public ActionJpaController(){ emf = Persistence.createEntityManagerFactory("IceCreamShopPU"); }

    private EntityManagerFactory emf = null;

    public EntityManager getEntityManager() { return emf.createEntityManager(); }

package org.persistence;

import jakarta.persistence.*;
import java.io.Serializable;
import jakarta.persistence.criteria.CriteriaQuery;
import jakarta.persistence.criteria.Root;
import org.logic.Role;
import java.util.ArrayList;
import java.util.List;
import org.logic.Action;
import org.persistence.exceptions.NonexistentEntityException;

public class ActionJpaController implements Serializable {

    public ActionJpaController(EntityManagerFactory emf) { this.emf = emf; }

    public ActionJpaController(){ emf = Persistence.createEntityManagerFactory("IceCreamShopPU"); }

    private EntityManagerFactory emf = null;

    public EntityManager getEntityManager() { return emf.createEntityManager(); }

40 replies

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•Created by Franscis123$# on 8/5/2024 in #java-help

How to check if a value coincide with any enum value?

I want to detect if a input values of a vector coincide with any value of a enum, I just got what detect if are entered in order, but I don't mind the order. (The same order what I declared the enum values). ```java import java.util.Scanner; public class EnumsNames{ Scanner key=new Scanner(System.in); public void ENames(){ enum Names{ Alejandra,Leonardo,Rosa,Guillermo,Gabriel,Daniel,Luisa,Ludmila } String[] name=new String[8]; for(int n=0;n<name.length;n++){ boolean valid=false; while(!valid){ System.out.println("Input a name:"); name[n]=key.next(); // In this if are my problem if(name[n].equals(Names.values()[n].toString())){ valid=true; }else{ System.out.println("Invalid name"); } } } }

8 replies

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•Created by Franscis123$# on 7/20/2024 in #java-help

Is possible print e.g. "X²" instead of "X^2" but the exponent as a variable?

In Java using Intellij IDEA is possible to print a variable like this "X²" (being "2" the variable) instead of "X^2"?

11 replies

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•Created by Franscis123$# on 7/18/2024 in #java-help

In Java, how to print only the value instead of "OptionalDouble[value]"?"

I printing a OptionalDouble matrix, and in the print, instead of print only the variable value, print e.g. "OptionalDouble[2.0]". I only want to print the value (2.0 in this example) and not "OptionalDouble[2.0]". The code: ```java import java.util.Scanner; import java.ultil.OptionalDouble; Scanner key=new Scanner(System.in); OptionalDouble[][] mat; mat=new OptionalDouble[3][3]; String YorN; for(int f=0;f<mat.length,f++){ for(int c=0;c<mat.length;c++){ System.out.print("Do you want insert a value? (Yes:Y / No:N)"); YorN=key.next; if(YorN.equals("Y")||YorN.equals("y"){ mat[f][c]=OptionalDouble.of(key.nextDouble()); } } } for(int f=0;f<mat.length,f++){ for(int c=0;c<mat.length;c++){ System.out.print(mat[f][c].toString()); } }

7 replies

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•Created by Franscis123$# on 7/17/2024 in #java-help

Java don't let me to use isEmpty

I declared a OptionalDouble as a marix, and I can't to use a if with isEmpty for this: if (polEXP_Lim[f][c].isEmpty()){ } All of this obviously inside of two for's Marks me the error in isEmpty. A way to solve it or an alternative to isEmpty?

5 replies

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