HibernateTest.java

// DEP: org.hibernate hibernate-core 5.2.10.final
// DEP: org.hsqldb hsqldb 2.4.0
// DEP: dom4j dom4j 1.6.1
// DEP: org.codehaus.woodstox woodstox-core-asl 4.4.1

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.util.HashMap;
import java.util.Map;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;

@Entity
class A {
	public int id;
	public int x;
	public int y;

	@Id
	@GeneratedValue(strategy=GenerationType.IDENTITY)
	public int getId() {
		return id;
	}

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

	public int getX() {
		return x;
	}

	public void setX(int x) {
		this.x = x;
	}

	public int getY() {
		return y;
	}

	public void setY(int y) {
		this.y = y;
	}

	public String toString() {
		return String.format("[%s, %s, %s]", id, x, y);
	}
}

public class Main {
	public static void main(String[] args) throws Exception {
		runSql("drop schema public cascade");
		runSql("create table a ( id int generated by default as identity, x int, y int );");
		runSql("insert into a values ( null, 1, 2 )");
		runSql("insert into a values ( null, 3, 4 )");

		SessionFactory sessionFactory = getSessionFactory();
		try {
			Session session = sessionFactory.openSession();
			try {
				System.out.println(session.createQuery("from A").list());
			} finally {
				session.close();
			}
		} finally {
			sessionFactory.close();
		}
	}

	private static SessionFactory getSessionFactory() {
		Map<String, String> config = new HashMap<>();

		config.put("hibernate.connection.url", "jdbc:hsqldb:mem:test");
		config.put("hibernate.connection.username", "root");
		config.put("hibernate.connection.password", "");
		config.put("hibernate.dialect", "org.hibernate.dialect.HSQLDialect");

		return new MetadataSources(new StandardServiceRegistryBuilder().applySettings(config).build())
			.addAnnotatedClass(A.class)
			.buildMetadata()
			.buildSessionFactory();
	}

	private static void runSql(String sql) throws Exception {
		Connection connection = DriverManager.getConnection("jdbc:hsqldb:mem:test", "root", "");
		try {
			PreparedStatement statement = connection.prepareStatement(sql);
			try {
				statement.execute();
			} finally {
				statement.close();
			}
		} finally {
			connection.close();
		}
	}
}