Spring Boot Saving/Reading entities running out of connections - spring-boot

Question

I am relatively inexperienced in using Java Spring/Hibernate. This problem may be easy to solve, but I feel like I have done hours of error look ups at this point. Here are some overall specs of my program: Using h2 database, database is locally stored, using spring-boot-starter, spring-boot-security.
Problem
I am trying to create an online Wiki. So far, I have not had any hiccups. I am able to save, update, and delete entities (which are called WikiPages). However, I noticed that if I try to read/save/update/delete a WikiPage around 5 times, the application is no longer able to communicate with my locally stored h2 server, the program hangs, and I am unable to view any webpages at all. I did not encounter this problem on my previous project which has a very similar DAO.
I have a suspicion that there is some sort of problem with my DAO interacting with the database. Any help would be appreciated. Please let me know if you would like to see a different file in the program. I enabled debug console logging
Application Properties
spring.datasource.url = jdbc:h2:tcp://localhost/~/Downloads/Data/Database
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect
spring.jpa.hibernate.ddl-auto=none
spring.h2.console.enabled=true
server.error.include-message=always
server.port=80
logging.level.org.springframework.web=DEBUG
logging.level.org.hibernate=ERROR
WikiPage
package com.costi.csw9.Model;
import lombok.EqualsAndHashCode;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import javax.persistence.*;
import java.time.LocalDateTime;
#Getter
#Setter
#EqualsAndHashCode
#NoArgsConstructor
#Entity
public class WikiPage {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "id", nullable = false)
private Long id;
#Column(nullable = false, unique = true)
private String title;
#Column(nullable = false)
private LocalDateTime lastEdited;
#Column(nullable = false)
private String subtitle;
private boolean enabled = false;
private String category;
#Column(columnDefinition="text")
private String body;
#OneToOne
#JoinColumn(name = "user_id")
private User author;
public WikiPage(String title, String subtitle, User author, String category, String body) {
this.title = title;
this.subtitle = subtitle;
this.author = author;
this.category = category;
this.body = body;
}
public WikiPage(User author){
this.author = author;
}
}
WikiDaoImpl
package com.costi.csw9.Repository;
import com.costi.csw9.Model.User;
import com.costi.csw9.Model.UserRole;
import com.costi.csw9.Model.WikiCategory;
import com.costi.csw9.Model.WikiPage;
import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.criterion.Restrictions;
import org.hibernate.query.Query;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import javax.persistence.TypedQuery;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Root;
import java.time.LocalDateTime;
import java.util.List;
#Repository
public class WikiDaoImpl implements WikiRepository{
#Autowired
private SessionFactory sessionFactory;
#Override
public WikiPage findById(Long id) {
Session session = sessionFactory.openSession();
WikiPage wikiPage = session.get(WikiPage.class, id);
session.close();
return wikiPage;
}
#Override
public List<WikiPage> findByCategory(WikiCategory category) {
Session session = sessionFactory.openSession();
CriteriaBuilder cb = session.getCriteriaBuilder();
CriteriaQuery<WikiPage> cr = cb.createQuery(WikiPage.class);
Root<WikiPage> root = cr.from(WikiPage.class);
cr.select(root);
cr.select(root).where(cb.like(root.get("category"), category.name()));
Query<WikiPage> query = session.createQuery(cr);
List<WikiPage> results = query.getResultList();
return results;
}
#Override
public List<WikiPage> getByApproval(boolean enabled) {
Session session = sessionFactory.openSession();
CriteriaBuilder cb = session.getCriteriaBuilder();
CriteriaQuery<WikiPage> cr = cb.createQuery(WikiPage.class);
Root<WikiPage> root = cr.from(WikiPage.class);
cr.select(root);
if(enabled){
cr.select(root).where(cb.isTrue(root.get("enabled")));
}else{
cr.select(root).where(cb.isFalse(root.get("enabled")));
}
Query<WikiPage> query = session.createQuery(cr);
List<WikiPage> results = query.getResultList();
return results;
}
#Override
public List<WikiPage> findAll() {
// Open a session
Session session = sessionFactory.openSession();
// Get all people with a Hibernate criteria
List<WikiPage> all = session.createCriteria(WikiPage.class).list();
// Close session
session.close();
return all;
}
#Override
public void save(WikiPage wikiPage) {
//Add in last edited
wikiPage.setLastEdited(LocalDateTime.now());
// Open a session
Session session = sessionFactory.openSession();
// Begin a transaction
session.beginTransaction();
// Save the person
session.saveOrUpdate(wikiPage);
// Commit the transaction
session.getTransaction().commit();
// Close the session
session.close();
}
#Override
public void delete(WikiPage wikiPage) {
// Open the session
Session session = sessionFactory.openSession();
// Not completley sure why I have to do this, but I need to find the page via id in this function
WikiPage page = session.get(WikiPage.class, wikiPage.getId());
// Begin translation
session.beginTransaction();
// Delete Page
session.delete(page);
// Commit the transaction
session.getTransaction().commit();
// Close the session
session.close();
}
}
Error
2022-06-28 20:35:22.933 DEBUG 10820 --- [p-nio-80-exec-4] o.s.web.servlet.DispatcherServlet : "ERROR" dispatch for GET "/error", parameters={}
2022-06-28 20:35:22.934 DEBUG 10820 --- [p-nio-80-exec-4] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController#errorHtml(HttpServletRequest, HttpServletResponse)
2022-06-28 20:35:22.935 DEBUG 10820 --- [p-nio-80-exec-4] o.s.w.s.v.ContentNegotiatingViewResolver : Selected 'text/html' given [text/html, text/html;q=0.8]
2022-06-28 20:35:22.935 DEBUG 10820 --- [p-nio-80-exec-4] o.s.web.servlet.DispatcherServlet : Exiting from "ERROR" dispatch, status 500

Answer 1

although I did not find what I did wrong in my code. I eventually go it to work with some light testing by turning as many DAO methods into JPA queries as I can. Hope this helps others!